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Research support

We have all been inpired by someone in the past to discover, protect and transmit natural wonders…. now it is our turn to inspire the world together 😉 

With the support of our local subject matter experts, you are equipped to successfully conduct your field research in your area of interest (among others: general and tropical biology, botany, herpetology, entomology, big / wild cats,  bats, squirrel monkeys, scarlet macaws, etc.)

 Osa Aventura offers all inclusive high quality field support to enhance the vision of professionals from all walks of life, including scientists, wildlife photographers, documentary filmmakers and artists, as it is our turn to inspire the world together.
For your convenience, prices include transportation, all meals, entry fees and the cost of the services of a bilingual expert, so that you can lay back and focus on taking in everything this place offers. 

Navigate the tabs and open the sections to view examples.

2019 – Tiffany Soukup

2018 – Animal Logic (Corcovado)

2014 – Nigel Marvin

2013 – Nigel Marvin (Top 10 Most Venomous Snakes of Costa Rica)

2013 – Swedish Television (Corcovado National Park)

2010 – White Hawk Foundation (Interviews)

2006 – Welsh Television (Presenter Yodo William)

2006 – Machaelias Wild Challenge

2005 – Machaelias Wild Challenge

2004 – Jeff Corwin in Action (as consultant)



2004  -2010  – ACOSA (Area of Osa Conservation) (Crocodile Survey)

1997 – 1998 – Department of Clinical Science, Queens University, Belfast (Collecting skin secretions from frogs for pharmaceutical analysis)

Herpetology Tour of Corcovado

Costa Rica is World´s Greenest, Happiest Country

Baird’s Tapir: The Gentle Giant of our Forests
The American Crocodile
The Bushmaster
The White-Lipped Peccary
The Sloth
Jewels of the Forest

A Night in the Jungle (by Kenneth Barnet)

Jewels of the Forest

Jaguar Encounters


Open the below sections

Herpetology Tour of Corcovado

A Report by Matt Harris,
a member of the Upstate Herpetological Association


Upstate Herpetological Association member Matt Harris, and former UHA President, Ken Barnett, led a group of 13 UHA members, relatives and NYSDEC biologists on a herping and birding trip to Costa Rica’s famed Corcovado National Park. Corcovado is situated on the remote Osa Peninsula in the Southeastern part of the country, only a stone’s throw from Panama . In the following article, you will learn about the abundant wildlife found there, which has prompted some to call Corcovado the ‘most biologically intense place on earth’. We encountered many herptiles and other animals on our trip, including poison dart frogs, white-lipped peccaries, Baird’s tapirs, American crocodiles, common caimans and deadly fer-de-lances!!

Part I: Arrival; hiking through Corcovado ; snakes and frogs galore!!

After getting a taste of the tropics in 2002, we decided if we really wanted to experience the remote, untouched Costa Rica , we need to do 2 things on the 2003 trip: 1) Go during the rainy season and 2) venture deep into the heart of Corcovado National Park . In 2002, I mentioned to Kenny that I wanted to go to Costa Rica to hunt for bushmasters. Within weeks, Kenny and his wife Gaye, decided they were going as well and we researched several ‘Eco-lodges’ and decided on a little known, no-frills lodge situated near Carate on the Pacific coast of the Osa Peninsula. This area, while remote, is still an 11 mile hike from the heart of Corcovado National Park – 11 rough miles along beach, over jagged, exposed rocks, through dense jungle and requires crossing 1 major river teaming with large crocodiles and bull sharks! And that’s assuming you’ve hit the tides just right!! While we saw an abundance of wildlife for only being our first time there (and you really can’t complain about trees with a dozen scarlet macaws squawking in it), we simply wanted to see the areas that were completely untouched by human encroachment.

Back in October I mentioned to Kenny, that this year, I was planning on hiking across the Osa Peninsula to get a first hand view of the more remote parts of Corcovado National Park . This particular hike follows a river from the Golfo Dulce on the north side of the Osa Peninsula , up through the lowland tropical wet forest, and finally up into the mountains on the northeastern boundary of the park where it enters at the Los Patos Ranger Station. From Los Patos, it follows a couple of knife-edge ridge tops and drops down onto the Corcovado plain, where it then follows the Rio Sirena and then the Rio Pavo on its way to the Sirena Biological Station and ranger station. The entire distance from the trailhead near La Palma on the North, to Sirena is approximately 17 miles. Logistically, the hike takes about 2 days if you spend a night at Los Patos and take time to explore the surrounding forests for animals, as well as, getting to the trailhead itself! The first 5 miles of the trail to the Los Patos ranger station takes you higher up into the hills and you enter the habitat of the black-headed bushmaster ( Lachesis melanocephala ). Kenny wasn’t keen on hiking and wanted to spend more time around the Sirena station, taking day hikes to explore the handful of trails that emanate from there. This was a result of researching journal accounts of the vast amounts of herpetofauna that have been catalogued in the area. In the meantime, we had made contacts with several herp-related researchers in Costa Rica , who further solidified the notion, that SIRENA IS THE PLACE TO GO!!!!!!

Sirena grass airstrip

Sirena grass airstrip

After much discussion (and extreme difficulty contacting the National Park service in Costa Rica to make reservations), Kenny decided to contact a gentleman, Mike Boston, whom we learned of through the lodge owner on last years trip. Mike actually leads treks into Corcovado National Park and is a connoisseur of fine Guaro. After contacting him, we decided to hire him to guide our trip. Rather than have just one plan, we decided to run to options: I would hike across the peninsula, with our guide Mike, while Kenny and Gaye would fly directly to Sirena (there is a small grass airstrip there—more on that later—it deserves a page all its own!!) Suddenly now, over the course of two months, the trip was actually becoming a reality.

In the meantime, through casual conversation, several UHA members expressed an interest in going along as well. Kenny had mentioned it through casual conversation at the DEC, and suddenly several biologists in the Endangered Species Unit were eager to go along as well. What started out as 3 now became 13!!!

On April 22 nd , we departed Newark for San Jose . After arriving around noon , we all piled into a van for the short ride to our hotel. Our luggage had only been thrown on the roof rack and wasn’t tide down so Kim Corwin kept a watchful eye out the back in case a piece fell off. After checking in and getting settled, we headed to the nearby bank to exchange money. One dollar equals approximately 350 Colones-the currency of Costa Rica . We leisurely strolled around San Jose and ate dinner at a local restaurant off of the pedestrian mall. The restaurant features wood roasted chicken served with the traditional beans and rice. Most Costa Rican dishes consist of beans, rice and some small portion of meat. It may sometimes contain fried plantains (baking bananas) or wild yams. In comparison to Mexican food, Costa Rican food is not as spicy, almost bland.

The next morning, we woke and ate breakfast. At this point I, Jim Chapman and his daughter Carrie left for our charter flight to the village of Puerto Jimenez , where we were to meet our guide, Mike. The rest of the group was to leave a little later for their direct flight to Sirena. Upon arriving at the airport, Jim, Carrie and I checked in and waited. Only about 20 minutes later, Kenny and the group arrived for their flight. Only then did they realize that their flight would actually occur in two stages—first a flight to Puerto Jimenez, and then a flight from PJ to Sirena. In fact, due to weight concerns, some of their luggage was going on our flight in a twin-prop commuter aircraft rather than their smaller Cessna. We arrived in Puerto Jimenez and met our guide. We then waited for the rest of the group, as Mike had to give Kenny some supplies (such as mosquito netting) to take to Sirena so we didn’t have to carry it on the hike.

After taking care of the gear and supplies, we departed with Mike into town to grab a bite to eat. It was only around 10:30am . Mike said we wanted to leave for the trailhead, which was about an hours ride, around noon and we should be hiking no later than 1PM in order to make the 3 ½ hr hike to the ranger station before dark. In the jungle, it tends to get dark much earlier. Our ride to the trailhead took about an hour to cover only 15 miles. When we got to La Palma , our driver stopped on a dime to point out the large male green iguana crossing the road. It was a beautifully impressive green iguana – unlike your typical pet-store iguanas! We continued on the dirt road that paralleled the Rio Rincon for about another mile until we could go no further. This was where the ride ended…..and the ADVENTURE BEGAN!

Dendrobates granuliferous

Dendrobates granuliferous

Late April is the end of the dry season in Costa Rica . The Rio Rincon at this time of year was only about knee deep in the rapids and waist deep in the bigger pools – of course, every big pool probably held a resident spectacled caiman ( Caiman crocodilus ). They usually hide in underground burrows under the banks and emerge at night to sit and ambush prey. Our hope was that the wet season would come early this year. As Mike had pointed out, the past years dry seasons had been exceptionally dry as had the previous year’s wet-season. We could only hope the rains would come. As we hiked along the river, we could hear the calls of Dendrobates granuliferous, the granular poison-dart frog from the steep, moss-covered slopes along the deeper pools. It wasn’t as hot and humid as we’d expected and a few brief afternoon showers cooled us off. It also helped wake up the frogs and bird life in the jungle canopy overhead. Mike kept pointing out the shrill, echoing call of the Chestnut-billed toucans high up the trees.

After an hour and a half of criss-crossing the stream more than a dozen times, the trailed made a hard right turn into a tall grove of heliconias. The trail then ascended a steep mud slope, rising about 400 feet in elevation through a series of switchbacks. Some sections were lined with circular discs cut from felled logs, but were not much help being covered with a slick layer of mud. Most of the Osa has a red-clay substrate. Mike heard the call of the bi-colored ant bird, and told us that when these birds are heard it means that there are usually army ants nearby. These ant birds habitually follow swarming army ants to feed on the arthropods that they flush from the leaf litter. In fact, ants dominate the tropical forests – we had to keep watching our step because the leaf cutter ants usually used the hiking trail like a super-highway and would stream 20 or 30 meters ahead before breaking off into the forest……they are an ABSOLUTELY AMAZING creature to watch! We spotted a small ‘rocket’ frog ( Colostethus flotator ), which is closely related to the Poison-dart frogs of the genera Dendrobates and Phyllobates .

Leaf cutter ants

Leaf cutter ants

After another hour or so, the trail started to go down. At one spot, the trail meandered back and forth around some trees and Mike pointed out that a friend of his had seen a bushmaster crossing the trail here several weeks ago—I could only drool! About 15 minutes later, we entered a clearing and off to the left stood the lone wooden, single-story building that is the Los Patos Ranger Station. Mike greeted the rangers warmly and enthusiastically – they were all his good friends, he explained! We dropped our packs and removed our shoes to let our feet breathe. Immediately behind and above us, high up in the canopy, a troop of Howler monkeys was frolicking in the trees. While staring up at the monkeys, a pair of toucans soared overhead into the trees. Mike pointed out some jars on a table that contained snakes preserved in alcohol. In one jar was the faded head of a black-headed bushmaster that the rangers had killed not too long ago – supposedly to protect visitors, but we were the last people who wanted protecting from awesome snake!!! Another jar contained a baby terciopelo but was almost white from the alcohol.

After about an hour of rest, during which we ate trail mix, candy bars, and tins of tuna and mixed vegetables we bought at the Pulperia in Puerto Jimenez, we were eager to begin exploring. Jim had bought plain tuna, and I thought I had gotten the same, but Jim saw my look of dismay when I opened mine up to see a bunch of mixed vegetables! My depression turned to satisfaction after I stirred it up and found some tuna underneath. READ ALL SPANISH LABELS CAREFULLY! It ended up being pretty tasty! We walked across the field, which serves as the pasture for the rangers’ packhorse, and headed down a trail. Not five minutes down the trail Mike caught a snake about 28 to 30 inches long. It turned out to be a juvenile tropical bird-snake ( Pseuetes poecilonotus ). It was starting to get dark and the frogs were starting to call so we kept searching. We kept hearing the shrill, high-pitched “TINK” of the ‘tink’ frog ( Eleutherodactylus diastema ) and homed in on one sitting on top of a tall fern. Another distinct call caught our ears, and turned out to be that of a glass frog ( Hyalinobatrachium colymbiphyllum ), which nearly drove us nuts! We narrowed the call to be emanating from a heliconia leaf, only to find a silent female sitting there. The call is so shrill, that when made close to the ear it seems to hit a resonance and make your ears ring, like someone struck a triangle right next to your head! We kept searching almost possessed to find the frog making this call, when suddenly a light bulb went on in my head. ‘Wait a second….’ I thought. I flipped the heliconia leaf over and sure enough, sitting on the underside of the leaf, clung the tiny little male. These are called glass frogs because their visceral organs can be seen through their transparent abdomens. They are orangish-green in color with small white dots. They are only about a half-inch long.

We searched for a little longer and found our second Leptodactylus bolivianus , a Central American leopard frog, which was sitting on a log. It was now pitch black out and we were watching it illuminated with our headlamps. While watching it, Mike noticed movement behind it, and saw the shadowy outline of a spiny rat ( Proechmys semispinosa ) sitting at the entrance of its burrow. This was exciting to me because the spiny rat is the primary food source of the bushmaster and terciopelo (even proven to us two days later)! We were definitely in bushmaster habitat! The jungle was loud with the calls of anurans everywhere around us…the rainy season had begun and we were in luck!! On the way back, something caught my eye the seemed out of place on a branch. I saw sticks coming out of a branch at right angles – that is odd for a tree. I looked closer and focused a little, and realized it was a lizard, a helmeted iguana ( Corytophanes cristatus ) sitting on the branch with its legs sticking out like Mr. Pretzel.

Around 7:45PM we went out for a second hike around the ranger station, this time just wandering around the pasture field. We went down near the rangers’ garbage pit and found no less than two dozen marine toads ( Bufo marinus ) stuck in the pit. The pit is about 10 feet square and about 5 feet deep preventing the toads from crawling out, but they all seemed happy. Mike picked up the eye-shine of a large Leptodactylus pentadactylus , the smoky-jungle frog, sitting just off the trail. We found several toads sitting in the pasture field, including Bufo haematiticus . Mike remarked that it was the largest one he had ever seen! This toad has very large parotid glands, but unlike most Bufo toads, has smooth warts giving it an appearance not like your typical ‘warty’ toad – hence it’s common name, the smooth-skinned toad!

Clelia clelia

Clelia clelia

We sat at a picnic table for about ½ hour just listening to the jungle sounds and wondering if the others arrived at Sirena all right. Jim, Carrie and I headed back to the station to turn. Walking by the steps, I noticed a small snake slithering underneath the porch. “SNAKE”-I had to whisper to Mike so I wouldn’t wake the rangers who were already asleep. Mike hurried up and dove after it under the porch. The station itself is raised about 3 feet off the ground and the under-story of the structure is completely exposed. Mike is a true adventurer: He grabs the snake first, identifies later! This little snake was the most brilliant shade of crimson I had ever seen—except for the small yellow ring around its neck. It was a juvenile mussurana ( Clelia clelia ). The mussurana is a notorious predator of the jungle, feeding on other snakes including bushmasters and fer-de-lance. Mike pointed out a peculiar fact about these snakes: they never bite when caught and handled. Perhaps that is fortunate, as the mussurana is a venomous, rear-fanged colubrid!! They are very large, beautiful, gentle snakes that turn a charcoal black after a couple years. In addition they are unique in being both rear-fanged (mildly venomous) as well as constrictors!!!! Carrie gave us her mosquito net to put it in so we could take it to Sirena to show the others. The temperature this evening at Los Patos was 81.1F at 4:30PM and dropped to 78.6F at 7:45PM .

The next morning we awoke around 6AM and hoped to depart by 7AM . After a couple cups of coffee and a pack of blueberry pop tarts, we started out around 6:40AM , a little ahead of schedule. About a half mile down the trail, Mike bolted ahead and grabbed a small, brightly colored snake. At first it appeared to be a coral snake, but I figured he must know what it is or he wouldn’t have grabbed it that quickly. On closer inspection it turned out to be a “false-coral snake” ( Erythrolamprus mimus or bizona ). The snake was absolutely gorgeous and was the closest mimic to coral snake I have ever seen, even more so than any of the tri-colored milkshakes of the genus Lampropeltis . Mike tucked the snake into a sock so it could make the journey to Sirena as well. We continued on for another 11 miles and around 3:30PM , we entered a clearing—SIRENA at last!!! Along the way, we crossed the Rio Sirena and Rio Pavo, both mere creeks this time of year, and descended from the highlands down onto the Corcovado plain passing an area where the jungle actually becomes more of a dry forest in sandy soil before again entering tropical lowland moist forest. We saw many leaf-litter frogs including Rana warszewitschii and Eleutherodactylus fitzingeri , which Mike pointed out, was quite common.

We relaxed on the veranda for about an hour after dropping our packs in the last remaining bunkhouse. Kenny immediately began rattling off all the various species they had seen. Al, Dave and Mike were recovering after losing a soccer game to “Team Holland”. Soccer? In 80-degree heat and 90% humidity? What were they thinking? Just before dinner we took the two snakes down the trail a short distance to show everyone. We found a sunny spot that would be good for photographs and opened up the booty. After a 10-minute photo-session, we released both snakes and went back for dinner.

After dinner, Mike led a hike down along the beach. Jim, Carrie and I decided to sit it out and relax on the porch of the Sirena Biological Station. I heard many stories of Jim’s insatiable appetite!

Baird's Tapir

Baird’s Tapir

After a few hours the group returned. They found a cat-eyed snake ( Leptodeira septentrionalis ) but while walking along the beach, encountered a pair of eyes glowing at them from the woods. They stood perfectly still not knowing what it could be, and after a few minutes a large mammal strolled out: a Baird’s Tapir ! It paused only inches from Al’s hand and he could feel its breath as it sniffed his hand. Absolutely amazing!!!

This concluded the end of day 3, and we still had 3 days to go!

Part II: Baby crocodiles; feisty peccaries; poison-dart frogs!!

The next morning, we woke and ate breakfast, which was usually served at 6:30AM . Oddly enough, while sleeping in the tropics, the sounds of the jungle tend to wake you early in the morning (invariably it was the resident troops of howler monkeys near Sirena, who begin their howling at around 4:30AM !). On most days, though I would wake up between 5 and 5:30AM , there were usually at least one or two people who had risen earlier and gone out for an early morning hike. We ate breakfast and afterwards, assembled on the porch of the Sirena station to go for a hike down to the beach. Mike suggested we take a stroll along the Guanacaste Trail, which eventually leads down to the beach near where the Rio Sirena empties into the Pacific Ocean .

Now, this is important! Along the one side of the Sirena station, between the kitchen and bunk area, there is step where you go out to the clothesline and spigot to get drinking water. Each day, we’d stroll out there several times to fill our water bottles. This morning, while heading out there, Carrie Chapman looked down and noticed a very large spiny rat ( Proechymys semispinosa ) lying dead next to the step….EEEwwww! Kenny and I looked at it and prodded it a few times to see how stiff it was….not very. We showed it to Al Hicks, because he is a mammal specialist. We roughed up the fur a little to see the coarse guard hairs (spines) which give it its name, but also noticed two areas where the fur was kind of moist like it was slobbered on. Kenny said “I bet this was killed by a snake of some kind”. I agreed, it looked very much the perfect size of that a large snake, such as a Terciopelo ( B. asper ) would eat and the distance between the puncture marks coincided as well. We found it odd that the animal was about 20 yards from the woods, though it was possible the snake (if that’s what it was) killed it and never trailed it.

As we approached the end of the Guanacaste trail, Mike motioned for us to stop. In the forest about 20 yds away stood a herd of white-lipped peccaries. We sat motionless watching them root up the dirt on the forest floor when all of a sudden they caught wind of us. “ CLACK-CLACK—-CLACK—CLACK—CLACK—–CLACK”- the silence erupted like someone had lit a string of cherry bombs! When startled, peccaries crack their teeth together and the sound of their molars slamming together makes a popping sound like exploding firecrackers. Mike whispered to us that white-lipped peccaries have the reputation of being the dangerous mammal in the Neotropics, and will not hesitate to attack if threatened!! So we quietly stood our ground, looking as unmenacingly as we could make ourselves, and let the herd speed off.

We walked a little further, and no one could avoid the putrid smell of dead fish. Mike explained that after particularly dry dry-seasons (which the area had just experienced), the first heavy rains flush the Rio Sirena with nutrients, accumulated over the dry months on the forest floor and dried up creeks, which deoxygenates the water, and that this kills the fish. Thousands of dead fish of all sizes floated down stream and littered the river banks. The black vultures were happy! And so was a bloated crocodile we encountered at the mouth of the river. This animal appeared to be a large male, approximately 8 feet in length. As we approached closer, the beast inflated its lungs with air exposing its back in a display to let us know he wasn’t happy we were around.

As we entered the beach area, Kenny approached a large impressive spiny-tailed iguana ( Ctenosaur similis ), which was basking on a log, to get some close-up video footage. After getting within about 6 feet of it, the lizard shot like a rocket toward the woods and into a hole. These lizards live in burrows right on the forest edge where it meets the beach. Down the beach about 15 yards, we found 3 other female ctenosaurs basking on the sand. These animals, though, were not as nervous and we approached them within about 5 yards while they grazed on various plant leaves along the bank.

After Lunch, our plan was for me to take about half of the group back up the trail to the Rio Pavo (about 3miles) and hike down the Rio Pavo—supposedly a few hundred yards—to where it empties into the Rio Sirena. Mike would take the other half of the group, and they would canoe up the Rio Sirena looking for crocodiles and meet us at the Rio Pavo. Then the two groups would switch and reverse the routes meeting back at Sirena around dinner time.

Our group included me, Kenny, Gaye, Jim, Carrie, Katie and Dave Edwards and we headed up the trail towards the Rio Pavo. About ½ hr into the walk, the skies clouded over and it started to rain. It hadn’t rained at Sirena since we had gotten there, and I hadn’t seen rain since day 1 on the Rio Rincon. The shower didn’t last long, maybe 20 minutes or so, and we didn’t get wet as most of the canopy protected us. We approached a small stream with just a trickle in it when I looked down and something hopping along caught me eye. “AURATUS” I shouted. A gorgeous, brightly colored adult Black and Green Poison Frog ( Dendrobates auratus ) was awakened by the morning showers. It was nice find, and apparently a rare one for the area – Mike later told us that in seven years of hiking the trails around Sirena he had never come across any. Without thinking, we caught it and held it to take pictures, but then made sure we thoroughly washed our hands off.



We came to the Rio Pavo and started heading down river…..around one bend and then the next. We walked several hundred yards, thinking that the Rio Sirena has to be around the next bend. We kept slogging through the river because the banks were high and steep in most places and covered in vegetation everywhere else. It seemed like forever and we stopped several times to rest and for Jim to catch up. His shoes were not holding up very well and it was slowing him down. Finally after at least an hour, we heard voices, and then thrashing through tall grass, Mike appeared on the bank. “Mike, it’s somewhat further than a couple hundred yards, more like a mile or so”, but we didn’t want to tell the others that. We were really glad we would be riding in the canoes on the way back. We asked Mike what they had seen, and he remarked that only a single caiman was spotted, no crocodiles. He had hoped to see some along some sandy areas where they nest as this was hatching season in Costa Rica .

After a half-hour rest, we loaded up the canoes: Kenny, Gaye, Katie and Dave in one and Jim, Carrie and I in the other. Not 50 yards down the trail, I spotted the ventral scales of a snake on a branch overhanging the river, about 20 feet up. ‘WHOA, there’s a snake up there’ I said. It took several minutes to point it out to Jim and Carrie as the pure white ventrals were tough to see and the snake was a blue color. We managed to get Kenny to turn his canoe around and we paddled over to where the tree trunk and exposed roots clung to the side of the muddy bank. The roots made somewhat of a natural ladder and I climbed out of the canoe while Jim and Carrie steadied the vessel. As I tried to climb up the tree, I realized, a trail of army ants was streaming down the trunk, and they began to bite me on the arms. As I re-thought my strategy, Kenny and the others kept an eye on the serpent trying to force it back in toward me. I finally just bore the brunt of the ants and was able to go maybe 8 feet up into the tree. Kenny grabbed one of the over hanging branches and shook it trying to deter the snake, but as he did, 3 bats flew out of the foliage and zoomed right across the water landing on the tree trunk mere inches from Carries head. They clung there for a few seconds. The snake, meanwhile crawled back toward me, and I got a somewhat decent look at its blue body noting it was around 5 feet long….have to ID that one later.

Baby crocs

Baby crocs

I descended out of the tree and back into the boat. Already we weren’t 5 minutes into the paddle and we found a snake….and a tough one to spot at that. Too cool! We proceeded down river, Kenny and Co. moving faster than our boat. We lost sight of them and we’re just going at our own relaxing pace, taking advantage of the silence, when I noticed a juvenile basilisk ( Basiliscus basiliscus ) right along the bank on a branch. On the water surface I saw two little bumps moving toward the lizard and tried to convince myself that there were moving and I wasn’t seeing an illusion. All of a sudden the bumps started rising out of the water…..then a couple tiny teeth…..then a snout…..HOLY SHNYKIES .A HATCHLING CROCODILE!!! “Oh My gosh….Jim stop…..A BABY CROCODILE!!!! LOOK!!!”…..we stopped the canoe but we drifted too close and the basilisk jumped into a bush. NUTS! We chased away the crocodiles meal…it would’ve been neat to see the croc grab the lizard. I scanned the shore to the left and Jim pointed out another one basking on a log to the left….a cute little foot-long baby sprawled on a log. HOW DID THE OTHER GROUP MISS THEM??? You gotta go slow and scan everything! I scanned to the right and suddenly could make out the pattern of little scales against a muddy bank…”Hey there’s anther one….an another…..and another……HOLY CROW….THERE ARE DOZENS OF THEM!!!”…They were everywhere! We started counting: Two, Four, Six,….Eight…..Too many to count and they were piled on top of one another.

“We gotta go get the others and show them!” … we tried to back the canoe out, but we were stuck. We tried not to splash, and almost started the babies but suddenly the canoe got loose as the babies appeared to be making a dash into the river. Don’t wanna spook them because we don’t know where Mama is!

We headed down stream at a fast clip…..hoping to find the others. They were about 200 yards ahead and we tried yelling to them about 100 yards away…..of course, they couldn’t hear us. Finally we caught up and told them we gotta go back, we found a gaggle of crocodiles (not the right term, but—hey, they’re close to birds!). We turned around and headed back upstream. We paddeled upstream, above the nest, and floated back down into place, allowing Kenny’s canoe to get closer for pictures. Gaye counted the babies and came up with 28 in number. There were probably more! I scanned the bank for signs of Mama, but found none. I spotted some turned up sand behind the tall saw grass on the bank and the sand was littered with broken egg-shells!!! THESE CROCS WERE MERELY A FEW DAYS OLD!!! WHOA!!!!!!!!!

Phyllobates vittatus

Phyllobates vittatus

We spent about 15 minutes watching the crocs and headed back down stream. We made it to the river mouth (where the big adult crocs live) around 4PM and tied up the canoes. The other group was running longer, and it wasn’t much before dinner when they arrived. Mike was exhilarated to hear of our discovery of a croc nest since they hadn’t seen them on the way up the river. He did bring back a neat find though, a Golfo Dulce Poison frog ( Phyllobates vittatus ). We had now seen all 3 species of poison dart frog endemic to the Osa Peninsula !

Part III: Large fer-de-lances; radio tracking tapirs; and the night- hike out!


After dinner, we decided to lounge around and take it easy. We had been hiking hard for the past 3 days and we all figured a relaxing evening would be nice to “recharge our batteries”. Talking to the two girls at Sirena, who do research on Central American spider monkeys, revealed that behind their cabin there was a water well around which was home to several Red-Eyed Tree Frogs ( Agalychnis callidryas ). This was only 50-75 yards from the lodge, so we figured that would be an easy hike to do tonight, and wouldn’t be too physically demanding. Around dusk (a little after 7 PM ) a group assembled and was starting to head back toward the well. We stopped along the forest and tried to home in on the call of a male red-eye tree frog which we heard calling from about 6-7 feet off the ground. Mike Adams found it right away, and it was a really neat site (being the first one I actually saw). It was much neater seeing a bright green frog perched on a leaf, with those huge red-eyes glowing back at you, rather than the dozens of emaciated frogs cooped up in screen cages at local herp shows.

We were all transfixed by the frog when suddenly we heard Carrie yell “SNAAAKKKKEEE….Get Matt there’s a snake under the porch”. Carrie had walked out to fill her water bottle and when she was coming back to the steps she saw the body of a very large snake crawling right next to the steps!! She immediately called Jim over and told him there’s a snake under the steps. Jim walked over, thinking it’s probably some tropical rat snake and at first glance, he couldn’t really tell with the poor lighting. He bent down to get a better look and upon seeing the large triangular spear-shaped head with black eye-stripe, knew right away….”Holy Cow, It’s a fer-de-lance!” Amazingly, this snake had followed the scent trail of the spiny rat that was laying there earlier in the day. We were right! It was a snake that had killed the rat and some 12-18 hours later, was able to follow the scent trail looking for the rat. It followed it at least 20 yards-the approximate distance from the forest edge to the steps!

Well, now everyone was running over to the station! Several of us asked where it was and I grabbed my hook, a small 24” cage hook-the only one I took on the trip. At this point, it was chaos. I jumped over the railing into the courtyard area and lay on my stomach to get a better view under the bunks. All we could hear were people yelling “It’s over here!”, “It’s going that way”, “and Everyone stay back!”… would have expected to see this snake flying around at Mach 2 with the way everyone was shouting, but when I finally saw the snake, it was very calmly coiling up next to a concrete support pedestal under the station floor. Someone asked “Are you gonna catch it?” to which I replied ‘Well, not with this hook!”. Mike and I deliberated what to do. We had no hooks (or catch bags for that matter) and at first I said “it’s probably best to just leave it there” as it was so far under the bunk area, no one could safely get it out. Mike said if we do that, the rangers will most certainly kill it for reasons of safety.

By now, a large crowd had gathered, including the monkey researchers, Jen and Sabrina, and Charlie Foerster, who studies the Baird’s Tapir ( Tapirus bairdii ) in Corcovado . Charlie said he had a butterfly net and a large pole we could use if we really wanted to capture the snake, but he too though we were nuts—this coming from a fellow who has survived a puma attack in 1996 while tracking tapirs! Mike went to ask the head ranger for permission to capture and relocate the snake, as even though, they are considered a nuisance, as with all Costa Rican wildlife within the park, it is illegal to capture it.

Martin, the ranger, and Mike returned. Mike showed him the snake and explained what we planned to do. Martin gave us permission, but requested we take the snake about 1 ½ km away on the other side of the Rio Sirena away from any hiking trails to release it. Charlie returned with a butterfly net and a coconut picker—a 7′ pole with 2 metal prongs on the end. Right away I figured it’d be difficult getting the snake out because the pole was so long, that as soon as I touched the snake, it would move like quicksilver and I would have no leverage lying on my stomach. It was exactly what happened. As soon as I touched the snake it shot down to the other end of the bunk house. I couldn’t drag it out because of all of the concrete supports pedestals supporting the station. We ran down to other end and found where the snake coiled. Fortunately with all the headlamps focused under the bunkhouse, the snake stayed there. By now the ladies who cook meals at Sirena, had gathered in the foray as well. They kept yelling “MUCHO LOCO, MUCHO LOCO!”—yeah we were nuts, but this is what we paid for!

A big terciopelo

A big terciopelo

We chased the snake back and forth a few times, and finally, the snake had enough, it decided to come out from under the building and (apparently) try to make a dash for the woods. Kenny was yelling “everyone get back and let it come out!” This way once it came out, I could deal with it in open ground. I ran around the corner of the building and saw the snakes head emerge….man this snake was gorgeous! And big, longer than either of my captive females, but not nearly as heavy—but still very healthy! I stood back until the snake completely emerged, but didn’t approach too close so I didn’t spook her (how exactly do you spook a 6′ terciopelo?). I snuck up from behind her and positioned the net in front of her head about 12 inches. When I had it in place, I gently tapped her tail, which usually is enough to make them explode like a coil spring! As soon as I tapped her, she lunged like a rocket straight forward into the net and as soon as I saw her tail disappear, I started twisting the net. I fully expected her head to come shooting back out of the bag and then I’d have to pin her with the pole and bag her by hand, but fortunately I got the net off the ground removing any leverage she had and got it twisted several times so she couldn’t come out. I laid the net on the ground and put my foot on the twisted section, and asked Mike to go get my laundry bag. We would slide that over it the net and “Double-bag” her. I asked Jim for a piece of parachute cord and first tied the net off, then Mike and I slid the laundry bag carefully over the net. Using another piece of para-cord, we tied off the laundry bag. My first Wild-caught Terciopelo! AWESOME! My heart was pounding, and the adrenalin was racing through my veins! Why watch Animal Planet, when you can do it yourself??? Mike was grinning from ear-to-ear! “Man, I love this!” he said in his Irish accent! “You guys are like a dream group for me!” So much for hunting red-eyed tree frogs!

I placed the snake and bag next to my bunk and checked it several times before I went to bed to make sure the knots were secure. I think I woke twice in the night too, just to make sure she was still in the bag. The next morning after breakfast, Martin accompanied a group of us along the beach and across the Rio Sirena to release the snake. Even though it’s a terciopelo, he wanted to be sure that the snake was released (and we weren’t gonna try to take it home with us) and that it was released far enough away from Sirena. The hike along the beach took about 2 hours to go release and get back to the Rio Sirena. The snake was very relaxed when it crawled out of the bag, not stressed at all and not aggressive like the stereotypical stories you hear about fer-de-lance (though, there are other times where they deserve this reputation, but most often they are quite placid animals). On the way back we stopped at a lagoon that was formed by what was once the course of the Rio Sirena. The river is constantly changing course, and this lagoon had a couple small crocodiles in it.

Mike planned to take the canoes back up the Rio Sirena to give the others who didn’t see the baby crocodiles a chance to see them and get some close-up pictures. The rest of us took a hike along the Espavales trail, a short trail, that we thought would be easy, to go see an enormous Ficus tree. This hike turned out to be one of the best of the trip. Hiking up the trail, Laura and I were in the back. Shortly up the trail, the others stopped. Now what? Gaye turned around and whispered “Peccaries”. Moving parallel to the trail came a wagon-train of white-lipped peccaries. Oh Boy! Now what are we gonna do? I immediately started looking for a tree to climb in, because these “pigs” were only about 10 yards away. I could hear Jim talking pretty loud and I thought…”what’s he doing? If we startle them, they may charge us!” On the other hand, Jim was thinking “If they know we’re here, we won’t surprise them, and they’ll turn around and run the other way”—which eventually worked. In the meantime though, Gaye was obviously concerned, because she would ask Jim what he thought, then turn around and in a whisper ask me what I thought, and be the messenger between two people who really had no idea what was gonna happen, but yet were trying to make the best out of a delicate situation. Fortunately, the pigs moved on, and we continued along the trail.

We came upon huge swarm of army ants spread out across the trail, so I stopped to observe them making little ant-bridges so the other ants had a short-cut over small ditches, saving valuable ant-time. As I stared down at two trails, I noticed how they oddly separated like a divided highway…that was odd. As I looked closer, coiled in this tiny island within a sea of ants, lay a baby female Terciopelo! Wow, and really cute too. I couldn’t leave it there or the army ants may attack and kill it. I found small stick, and used it to gently pin the snakes head to the ground so I could get a grip behind the mandibles. Using the 3-finger approach, I pinned the snakes head, grasping it with my index finger between the supraocular scales and my thumb and middle-finger behind the mandibles. I picked it up to show everyone then carried it up the trail about 100yds and release it. Boy, what a cute little snake.

We stumbled upon a troop of squirrel monkeys making all kinds of racket in the canopy. We soon realized why: Two white hawks were perched above the troop and watching the monkeys feeding. All of a sudden with a flash of white, the canopy erupted with monkey-chatter and limbs shaking and one of the hawks dropped down and grabbed a baby squirrel monkey! Monkeys were screaming, limbs were shaking and the whole forest was alive!!! And as quickly as it came alive, it was quiet again, almost as if the monkeys accept that they’ll lose a baby every now and then to the winged predators. Such is the equilibrium of life that still exists in ecosystems that are undisturbed by people.

After Lunch, we took a hike up the Rio Claro to search for dart frogs. After the long hike and canoe trip the previous day and the excitement of the night before, Mike suggested an easy hike up the river and the chance to take a swim to cool off. Up this river, Mike has found Dendrobates granuliferous , the granular poison frog, high up in some stream beds that empty into the Rio Claro . We figured it would be a nice hike since we could take a dip in the river on the way back. After slogging through the river upstream for about a mile, we came to a tiny stream cascading down a moss covered ravine. Mike located a tiny ‘ granuliferous’ calling from a moss covered cliff. The hike up this little ravine was very slippery and it was tricky climbing up without slipping on the wet rocks. After taking pictures and fruitfully scouring the leaf litter for what we thought was another granuliferous (it turned out to be a leaf-litter frog…possibly Rana warszewitschii ) we head back to the Rio Claro . We found a nice long pool for a swim with a rock ledge on the far bank that made a nice under-water bench. We swam for a half-hour and headed back to the lodge. We arrived in time to change into dry clothes and shower before dinner.

After dinner, we took a short hike along the stream next to the ranger station to look for spectacled caiman ( Caiman crocodylus ). The streams are low still, and generally only the larger pools hold deep water. Each deep pool is home to a resident large caiman, anywhere from 4 to 6 feet in length.

Next morning (it was now Sunday, the 27 th ), we took a leisurely hike to the beach to go swimming. In the afternoon, Mike decided to take a hike higher up into the hills behind Sirena. Since it had some steep climbs and we were pretty tired from the past week, several of us decided to skip this hike. Jim, Carrie and I declined because we knew we’d need our energy for the 11-mile hike to Carate that night. Mike asked Charlie if he would take those of us, who hadn’t seen a tapir, out to try to find a tapir. Charlie agreed and said we could find one only a short distance away, and it would be an easy walk. We went up the Los Patos trail only a couple hundred yards and turned onto a ‘research trail’ marked only with plastic ribbons. In the middle of a of some vines between two small streams we found “Big Mama”, a 600lb tapir with her 6-month old baby, “Nepal”. They allowed us to watch them for several minutes and then waded into a stream before disappearing into the jungle. What a sight! How many people ever get the chance to observe a wild-tapir from merely 30 feet away? (For more info on the Baird’s Tapir, see the link at the end of the article).

The others returned from their hike around 5 o’clock , and exclaimed that they found a large female terciopelo even bigger than the one we released! This one was coiled in the forest with a litter of newborn babies! They had only found her because they went off trail following what sounded like screams of a monkey in distress: That usually means a jaguar nearby!!

That evening, we lounged around the lodge and prepared our gear for the next day’s departure. The four of us hiking out, prepared our day packs, as Mike suggested we send our gear on the planes, to save weight for the hike. We took only enough snacks and water plus our headlamps and first-aid kit with us on the hike. This would allow us to cover the 11 miles quicker and we could leave later getting an extra hour of sleep.


We woke around midnight . It didn’t take long to pack up and be ready to go. I drank lots of water the evening before, so I was well hydrated. I checked the battery in my headlamp and had a spare…Let’s go!

We waited for Mike Adams, as he decided he wanted to hike out for the adventure, rather than fly out. We started down the airstrip around 1 AM and turned into the forest where the trail to Carate begins. This trail must be followed at the right time of day, or A) you will become overcome with heat stress while hiking along the beach or B) You’ll be stuck waiting at certain points where you cross rocky promontories which can only be crossed at low-tide. In either case, day or night, you have to wade through two rivers (the Rio Claro and Rio Madrigal), and the first one is inhabited by large crocodiles, and on occasions bull sharks! The bull shark is the only requiem shark which can tolerate both salt and fresh water, and frequents rivers and estuaries. It is also the shark responsible for the most attacks on people! So understandably, we waded across the Rio Claro with some trepidation! With the red glow of a few crocodile eyes to remind us of their presence, and ensure an ample infusion of adrenalin in our veins, we crossed without incident. We lost no hikers, but we lost the trail on the other side! Recent storms had knocked down trees and the trail, at 1 in the morning, was impossible to find. Mike started to slash a trail through the jungle using his machete. Fortunately, the trail follows the beach most of the way, so as long as we heard waves crashing, we wouldn’t get lost. The problem was, it was going to take us 6-7 hrs to get to Carate with no delays, and if we had to bushwhack that could easily double the time!! Mike hacked his way out to the beach and we walked the beach a ways until we found the trail again. We stopped at a point where the beach entered a grove of coconut palms when Jim noticed he lost his glasses. He was having trouble with an eye infection, and stepped on a coconut, nearly twisting his ankle. He knew right away where he lost his spectacles, so he and Carrie backtracked and after about 20 minutes, returned, having found the glasses. We now had to navigate a promontory, called Salsipuedes, which means “pass if you can”. It is a barrier at high tide, and its black volcanic rocks are sharp and slippery at low tide!

We navigated it with few difficulties and made our way along the beach, sometimes, going inland. We stayed close to the surf. We were lucky that the tide was ebbing as the wet sand near the is harder and easier to walk on compared to the dry soft sand further up the beach. At the halfway point we had another rocky promontory to cross, called La Chancha. This too presented us with a formidable barrier of sharp rocks, and also poses a problem at high tide. We were thankfully that Mike had hiked this trail many times and knew the ropes!

Normally, if you hiked this trail, you’d be asking for trouble to do it in the daytime because of the exposure to the sun. At night, though, it’s cool and we took full advantage of the ebbing tide to make good time. The sunrise was truly spectacular. Mike pointed out a sea-turtle floating out in the surf. We passed the hull of an old shipwreck shortly before approaching the Rio Madrigal. We had one more area of wet rocks to cross and after getting over them, we stopped at a stream that was spring fed, in case we need to refill our water bottles. Jim wasn’t doing well. For the past several hours, he was running a fever and had vision problems with his eye-infection. We decided at this point, that we would all make it to the Rio Madrigal together (merely another 1km), and then Mike and I would go ahead to the Pulperia (store) in Carate to wait for the taxi. If Jim, Carrie and Mike A. didn’t make in time, we’d have the taxi wait for them. It was now 6AM .

Just an hour later, Mike and I arrived at the Pulperia, covering the last three and a half miles at a brisk pace – the prospect of a cold beer hastened this pace towards the end!! Amazingly, the others were only a half-hour behind us, arriving at 7:30AM . Jim was feeling better by then, being able to move at his own pace, rather than the grueling sprint we were setting. In the meantime, we relaxed, slaking our thirsts with a few more beers and sodas, compared notes on our many aches and pains, and waited for the colectivo taxi to arrive.

During the last six days, we had hiked over 35 miles through steamy jungle, waded across croc and shark infested rivers, and along deserted beaches. We had bagged a 6′ Fer-de-lance, canoed with crocodiles, and confronted white-lipped peccaries, and survived un-scathed! It was time for a rest. We all slept on the near 2-hr collectivo ride around the peninsula back to Puerto Jimenez. We weren’t there long when Kenny and Dave Adams strolled into Carolina ‘s Restaurant in Puerto Jimenez. We were starved and chowed down on burgers and Coca-colas, which we were craving!

For more info on the Bairds Tapir Project, Proyecto Danta , or to adopt a Tapir, such as ‘Big Mama’, you check out Charlie’s website at:


Costa Rica is world's greenest, happiest country

Costa Rica is world’s greenest, happiest country

Ashley Seager, Saturday 4 July 2009 05.00 BST

Latin American nation tops index ranking countries by ecological footprint and happiness of their citizens

A rainbow over San Jose in Costa Rica
A rainbow over San Jose in Costa Rica. Photograph: Juan Carlos Ulate/Reuters

Costa Rica is the greenest and happiest country in the world, according to a new list that ranks nations by combining measures of their ecological footprint with the happiness of their citizens.

Britain is only halfway up the Happy Planet Index (HPI), calculated by the New Economics Foundation (NEF), in 74th place of 143 nations surveyed. The United States features in the 114th slot in the table. The top 10 is dominated by countries from Latin America, while African countries bulk out the bottom of the table.

The HPI measures how much of the Earth’s resources nations use and how long and happy a life their citizens enjoy as a result. First calculated in 2006, the second edition adds data on almost all the world’s countries and now covers 99% of the world’s population.

NEF says the HPI is a much better way of looking the success of countries than through standard measures of economic growth. The HPI shows, for example, that fast-growing economies such as the US, China and India were all greener and happier 20 years ago than they are today.

“The HPI suggests that the path we have been following is, without exception, unable to deliver all three goals: high life satisfaction, high life expectancy and ‘one-planet living’,” says Saamah Abdallah, NEF researcher and the report’s lead author. “Instead we need a new development model that delivers good lives that don’t cost the Earth for all.”

Costa Ricans top the list because they report the highest life satisfaction in the world, they live slightly longer than Americans, yet have an ecological footprint that is less than a quarter the size. The country only narrowly fails to achieve the goal of what NEF calls “one-planet living”: consuming its fair share of the Earth’s natural resources.

The report says the differences between nations show that it is possible to live long, happy lives with much smaller ecological footprints than the highest-consuming nations.

The new HPI also provides the first ever analysis of trends over time for what are supposedly the world’s most developed nations, the Organisation for Economic Cooperation and Development (OECD).

OECD nations’ HPI scores plummeted between 1960 and the late 1970s. Although there have been some gains since then, HPI scores were still higher in 1961 than in 2005.

Life satisfaction and life expectancy combined have increased 15% over the 45-year period for those living in the rich nations, but it has come at the cost of a 72% rise in their ecological footprint. And the three largest countries in the world – China, India and the US, which are aggressively pursuing growth-based development models – have all seen their HPI scores drop in that time.

The highest placed western nation is the Netherlands. People there live on average over a year longer than people in the US, and have similar levels of life satisfaction – yet their per capita ecological footprint is less than half the size. The Netherlands is therefore over twice as environmentally efficient at achieving good lives as the US, Nef says.

The report sets out a “Happy Planet Charter” calling for an unprecedented collective global effort to develop a “new narrative” of human progress, encourage good lives that don’t cost the earth, and to reduce consumption in the highest-consuming nations – which it says is the biggest barrier to sustainable wellbeing

Baird's Tapir

Osa Safari: Baird’s Tapir The Gentle Giant of our Forests
by Mike Boston of Osa Aventura

Baird’s tapir

Baird’s tapir

Visitors to Corcovado National Park are very often treated to an encounter with Baird’s tapir, the largest mammal native to the Neotropics. Upon meeting one of these lumbering beasts one is immediately impressed by how docile and benign it is – a real gentle giant of our forests!

Baird’s tapir, Tapirus bairdii, is the largest of three species found in the rainforests of Neotropics – an adult male can weigh up to 300 kilograms (660 lbs). It ranges from southern Mexico through Central America and into western Columbia and Ecuador. Tapirus terrestris, the Brazilian tapir, inhabits the lowland rainforest from Venezuela to northern Argentina, and T. pinchaque, the mountain tapir, is confined to the dwarf forests and paramo of the Columbian and Ecuadorian Andes. A fourth species, T. indicus, the Asiatic tapir, ranges through Burma, Thailand, the Malay Peninsula and Sumatra. The Asiatic tapir is the largest of the four species and its white and black coloration contrasts to the somber brownish-gray coloration of the Neotropical species. Young tapirs of all species are dark reddish brown with white stripes and spots, a coloration they retain for their first 5 to 8 months.

Tapirs are odd-looking beasts, to say the least: robustly built and rather rhinoceros-like, but without the horns, and with a flexible, trunk-like nose and upper lip. Their limbs are stout with three load-bearing toes on each foot, placing tapirs within the odd-toed ungulates or Perissodactyla. This order of large, herbivorous mammals also includes the horses and rhinoceroses.

The Perissodactyla reigned supreme as the dominant herbivores of the northern hemisphere in the middle of the Tertiary era, reaching their greatest diversity from 45 to 20 million years ago. Its members included the largest land mammals ever to have lived: Megatherium, for example, a huge rhinoceros-like animal, weighed in at an impressive 20 tons – four times the weight of a large, bull elephant!

The supremacy of the Perissodactyls, however, was to wane towards the later half of the Tertiary. The even-toed ungulates, or Artiodactyls began to gain the upper hand as the northern hemispheres dominant herbivores. Their large ruminating, four-chambered stomachs made the Artiodactyls more efficient than the Perissodactyls at processing the rather coarse, indigestible vegetable mater upon which they depended. – It has always seemed to me to be a rather odd quirk of evolution that the ungainly, and dull-witted cow should have gained supremacy over the graceful, and relatively intelligent horse!

Of the fifteen families, and numerous species, that represented the Perissodactyls in their hay-day, only three families and seventeen species survive today. All but a handful of these species are threatened with extinction – it is only through the good fortune of their mutualistic association with man that Equus caballus, the horse, and E. asinus, the ass, have gained a secure future!

Of the three remaining families of Perissodactyls, it is the rhinoceroses (Rhinocerotidae), and the tapirs (Tapiridae), that are more closely related. Each share more features in common than either does to the horses (Equidae). Among these shared features are the possession of three load-bearing toes on their fore and hind feet – though, the tapirs do possess a fourth toe on their fore feet, which bears load only in swampy terrain. Horses, asses and zebras, as you know, have one load-bearing toe.

Tapirs are browsers of forest habitats, feeding mainly on leaves, though fruit and grasses comprise a significant portion of their diet. Tapirs favor riparian habitats along river courses, swamps and the fringes of bodies of water. They often feed partly submerged in water on floating herbaceous vegetation. Tapirs are very accomplished swimmers, and it is not uncommon in Corcovado National Park to see Baird’s tapir swim considerable distances under water.

Baird’s tapir, like its relatives, are solitary animals, and strongly territorial. Males hold large territories that include the territories of perhaps several females. Characteristically for the Perissodactyls, Baird’s tapir has a long gestation period of 13 months, after which a single young is born (very rarely two) and remains in its mothers care for about a year.

Tapirs have an acute sense of smell and hearing, but relatively poor eyesight. They tent to be more active at night, but in Corcovado, Baird’s tapir may be encountered during the day, especially in the afternoons in wallows or in rivers. Tapirs communicate over distances with long whistles; grunts, hiccups and whimpers at close range. On their browsing forays, tapirs tend to use regular, well-worn trails through the forest. These trails often form deep cuts along riverbanks at their regular crossing points.

Baird’s tapir is list by CITES in Appendix 1: ‘rare and local’. The major threat to the species comes from habitat loss and hunting. They are not a regular item on the jaguars’ menu – which may in part account for their rather nonchalant manner when encountered in Corcovado. Females will defend their young quite aggressively, but in most other circumstances these animals have an aura of benign indifference when encountered. In this respect they couldn’t be more different to the feisty, neurotic and aggressive peccary.

Mike Boston is a biologist, wilderness expedition guide, and the president of Osa Aventura. You can contact him at at [email protected]

The American Crocodile

Osa Safari: The American Crocodile
by Mike Boston of Osa Aventura

The American Crocodile (Crocodylus acutus) is one of four species of crocodile found in the New World Tropics (Neotropics). It is the most widespread of the New World species, ranging from the tip of Florida through southern Mexico and Central America to Venezuela, Colombia and Ecuador. It is also found throughout many of the West Indian islands. The other three species have very restricted distributions: the Orinoco crocodile to the Orinoco river basin; Morlete’s crocodile to southeastern Mexico and Belize; and the Cuban crocodile to western Cuba. The latter two species are relatively small crocodiles, seldom exceeding 3 meters in length. However, the American Crocodile, and its sibling, the Orinoco Crocodile, are reputed to reach lengths in excess of 6 meters—and well over one ton in weight! They share the dubious distinction, therefore, of being the largest predators in the Neotropics – a title the American Crocodile alone holds in Central America! However, not that long ago geologically speaking, Porosaurus reigned supreme as one of the largest non-marine predators of all time. This monster crocodile, reaching 16 meters (50 feet) and weighing over 18 tons, terrorized the Amazon Basin up until about 6 million years ago. Its fossilized skull alone weighed 500 kilograms!

An excellent photo to illustrate the differences between crocs and alligators

This photo shows a common caiman (bottom left) american crocodile (bottom right) and missippi alligator (top). An excellent photo to illustrate the differences between crocs and alligators

Like all crocodilians worldwide (with the possible exception of the Common Caiman), the American Crocodile is threatened with extinction. And like all of its relatives, it has been hunted mercilessly for its skin. In an attempt to rescue this specie from possible extinction, the Convention on International Trade in Endangered Species (CITES) placed the American Crocodile on Appendix 1 (Endangered) in the 1970s, preventing further trade in hides and live specimens among signatory nations. However, thanks to Costa Rica’s rigorous conservation laws and its present system of protected wetlands, this country has ensured a secure future for this majestic crocodilian within its borders. Costa Rica is perhaps the only country in its range where the American Crocodile is still relatively abundant. On both versants of the country sizeable specimens of the American Crocodile can be seen frequently in swamps, tidal estuaries and sluggish rivers. I, personally, have seen American Crocodiles of over 4.5 meters on the upper Río Sierpe, and have been assured by several Park Rangers that 5 to 6 meter specimens live in and around the Corcovado Lagoon in the heart of Corcovado National Park!

The American Crocodile shares its amphibious world in this country with the Common Caiman (Caiman crocodilus). The two species are often confused with one another. However, both represent distinct lineages within the crocodilian reptiles: the American Crocodile is a true crocodile (family Crocodilidae), whose members are pan-tropical; the Common Caiman is in fact an alligator (family Alligatoridae) whose members are confined to the New World (with the curious exception of the Chinese Alligator). The best known member of this group is the Mississippi Alligator from the Southeastern United States. The Common Caiman seldom exceeds 2 meters in length, but the following characters can readily tell specimens of similar size of both species apart:

  • The common caiman is dark brown in color with distinct black bands on its tail; the American Crocodile, on the other hand, is drab olive green, and the black markings on its tail do not form bands.
  • When basking on a riverbank, a Common Caiman will generally hold its head up; the American Crocodile will rest its head on the ground.
  • The snout of the Caiman is shorter and more rounded, with its eyes and nose more prominently raised; the American Crocodile has a longer, narrower snout, with less prominently raised eyes and nose.
  • From a dorsal view, the snout of the Caiman is not constricted behind the nose; that of the American Crocodile is distinctly constricted
A baby crocodile

A baby crocodile

When its mouth is shut, only the teeth of the upper jaw of the Common Caiman are visible; the teeth of the lower jaw slot into the upper jaw. In the American Crocodile, however, the teeth of both the lower and upper jaws are both visible

When its jaws are shut – look for the large fourth tooth of the lower jaw which slots into the constriction of the upper jaw behind the nose.

Another difference between the American Crocodile and the Common Caiman is in their habitat preference. Although they cohabit many fresh water areas, the latter is in ways more adaptable and will even inhabit watery ditches, transient pools, and fast flowing creeks. The Common Caiman will rarely, if ever, stray into brackish river estuaries, and never into the sea. The American Crocodile is choosier in its freshwater habitats, favoring lakes, lagoons and sluggish rivers. However, it shares with the Indo-Pacific Crocodile the unique ability to utilize salt-water habitats, such as tidal estuaries, mangroves and the sea. I have often seen American Crocodiles in the seas around the Osa Peninsula, even feeding at sea in front of the Río Sirena, in Corcovado.

Mike BostonWe all regard crocodilians as primitive beasts and, let’s face it, their appearance serves only to reinforce this view. But, behind that primordial guise lies a sophisticated animal indeed. We traditionally refer to them as reptiles, with all the lowliness that this grouping implies. But current taxonomic wisdom has elevated the crocodilians to a loftier status and grouped them along with the birds. They share many features and behaviors in common, among them a four-chambered heart (mammals too have four-chambered hearts, but of a different configuration to that of birds and crocodiles) and a sophisticated system of parental care. Snakes, lizards and turtles have two-chambered hearts and rarely engage in any form of parental care. And crocodilians have larger brains than their former reptilian group-mates.

The American Crocodile, like other crocodiles and alligators, guards its eggs throughout the 90-day incubation period from nest robbers such as raccoons, coatimundis, and ocelots. It buries its clutch of about 30 eggs in sandy riverbanks – a characteristic shared with other true crocodiles; alligators bury their eggs in mounds of vegetation. Favorite nesting sites (for example the sandy banks around the Río Corcovado) may be crowded with the nests of many female American Crocodiles. Alerted to the guttural grunts of their hatching young, the female will help unearth them, grasp each of them gently in her powerful jaws and carry her hatchlings to a secluded watery hideaway. The female American Crocodile will then remain in protective care of her young for many months untilthe last one has dispersed.

American Crocodiles of over 3 meters are potentially dangerous to man. Although they don’t have the fearsome reputation of the Indo-Pacific Crocodile of Asia and Australia, or the Nile Crocodile of Africa, nevertheless there have been several cases where American Crocodiles have attacked and killed people in Costa Rica. However, despite their lethal capability, large American Crocodiles are for the most part surprisingly timid beasts. Unless one is foolhardy enough to swim in water that large crocodiles are known to inhabit or to venture too close to a female protecting her nest or young, one need fear little from the American Crocodile.

Crocodilians and their ancestors lived on Earth for over 200 million years and have survived two mass extinctions: 1) the first at the end of the Permian Period, which wiped out 95% of all species, and 2) the second at the end of the Cretaceous, which put pay to the dinosaurs. Let us hope the American Crocodile and its relatives, in all their primeval splendor, can survive this, the next possible mass extinction, into which the natural world of this planet has now entered.

Mike Boston is a biologist, wilderness expedition guide, and the president of Osa Aventura. You can contact him at at [email protected]

The White-Lipped Peccary

Osa Safari: The White-Lipped Peccary
by Mike Boston of Osa Aventura

The white-lipped peccary (Dicotyles pecari) is one of two species of peccary found in Central America. It is larger than its sibling species, the collared peccary (Tayassu tajacu), and more specific in its habitat requirements. Throughout its range, from southern Mexico to northern Argentina, the white-lipped peccary is confined to undisturbed primary rainforest. The collared peccary, the larger range of which extends further north into the southern United States, is able to utilize a variety of habitats from semi-desert to rainforest. A third species, the Chacoan peccary (Catagonus wagneri), is restricted to the Gran Chaco region of Paraguay, Bolivia and northwestern Argentina. It is the largest of the three known species of peccary. However, there are reports of a fourth species of peccary having been discovered in the depths of the Amazon basin. This amazing find awaits confirmation and published description – and even more amazing is that this discovery includes twelve new species of monkey, five new species of bird and a new specie of deer!

Peccaries are often referred to as wild pigs. Indeed, the local name for the white-lipped peccary is chancho de monte. However, the resemblance is merely superficial. Peccaries are not true pigs. The similarity between true pigs and peccaries is an example of convergent evolution, resulting from the fact that they both evolved independently to occupy similar ecological niches – omnivorous rooters. True pigs (family Suidae) – which include the wart hog of Africa, the babirusa of Sulawasi, the wild boar of Eurasia (from which the domestic pig is derived), among others – evolved in the Old World along parallel lines to the Peccaries, (family Tayassuidae), in the New World. An obvious difference between the two families is that in true pigs (especially pronounced in males), the upper canine teeth grow outwards and upwards forming clearly visible tusks. The upper canines of peccaries grow downwards and are not visible from the outside when their mouths are closed. In both families, the enlarged canine teeth represent formidable weapons.

Armed with long, self-sharpening canines and irascible temperaments, white-lipped peccaries are considered to be the most dangerous mammal in the Neotropics. Their redoubtable reputation is compounded by the fact that white-lipped peccaries live in large herds of 30 to 200 individuals.

The White-Lipped PeccaryIn Corcovado National Park it is not uncommon to encounter herds of white-lipped peccaries of fifty or more individuals. And these encounters are charged with tension. It is without doubt one of the most sensational experiences to find oneself amid a herd of these belligerent beasts. Beyond a certain threshold distance, white-lipped peccaries will generally run off when alerted to human presence. However, within that threshold distance they will stand their ground, and sometimes charge. Under these circumstances it is advisable to climb a tree, if possible – if not, then stand your ground!

With their bristly hairs erect along their backs, it is the males who will most vigorously defend the herd, especially if there are young present. The commotion they create, grunting, barking and loud, spine-chilling clacking of their formidable canine teeth, is enough to make one’s own hairs stand on end. And with the air around rank with their fetid stench, it is rather as though all hell has broken loose!

Peccaries give birth to relatively few young – from one to three, but usually twins – which are well developed and able to run around soon after birth. This contrasts with true pigs, which give birth to large litters of helpless young.

Another difference between true pigs and peccaries is that the latter uses scent to maintain herd cohesion and to mark herd territories. Peccaries have large scent glands on their backs towards their rumps from which they secrete an oily musk with a strong, pungent smell. Very often it is their smell, described as skunk-like, that initially alerts one to the presence of peccaries.

Peccaries, like true pigs, belong to the order Artiodactyla, the even-toed ungulates. They share a common ancestry, therefore, with herbivorous mammals such as deer, goats, sheep, antelope, camels, and cattle. However, peccaries, and true pigs, show an evolutionary tendency toward carnivory. Indeed, up until about 10 million years ago a huge, one-ton, predatory pig terrorized the plains of North America.

The diet of white-lipped peccaries is varied, and includes seeds, nuts, fruit, roots, and vegetation. They will also eat carrion, and live animals such as insects and their grubs, and even snakes. Their powerful jaws make them the only herbivorous mammals able to exploit the hard nuts of the raphia palm, a particularly favored food source for white-lipped peccaries.

White-lipped and collared peccaries exist side-by-side throughout much of their range, and they may easily be confused with one another. The two species differ in size – up to 75 lb and 22 inches at the shoulder for the white-lipped peccary, and 45 lb and 18 inches for the collared peccary – but unless seen together for comparison, size may not be a reliable means of distinguishing the species. Herd size and/or coloration are more reliable distinguishing characteristics: white-lipped peccaries forage in large herds, rarely less than 20 individuals and usually many more. The fur on the cheek and lower jaw of this species is cream/white. Collared peccaries, in contrast, forage in much smaller herds, usually less than 10, and rarely more than 15 individuals. While their grizzled, dark gray/brown coloration is similar to the former species, the collared peccary lacks the white chin patch. Although not always noticeable in the field, the collared peccary has a cream-colored collar running from its shoulder to its chest.

White-lipped peccaries are placed by the Convention on International Trade of Endangered Species (CITES) in appendix II – threatened! Because of their narrow habitat preference – undisturbed primary rainforest – white-lipped peccaries are particularly vulnerable to habitat destruction. As a result of widespread deforestation, populations of white-lipped peccaries in Central America have become fractionated, and reproductively isolated. And, as if this is not bad enough, these peccaries are great to eat and mercilessly hunted. In fact, it is hunting that threatens the still sizable herds of white-lipped peccaries in Corcovado National Park – the largest population of the specie left in Costa Rica.

Mike Boston is a biologist, wilderness expedition guide, and the president of Osa Aventura. You can contact him at at [email protected]

The Bushmaster

Osa Safari: Bushmaster
by Mike Boston of Osa Aventura

It is huge, rare and shrouded in mystique. No other snake in the New World inspires such reverence and dread within us than the mighty bushmaster. At over 4 meters, it is the largest viper in the world. And one of the deadliest!

Myth and legend surround this snake wherever it is found, and this is reflected in its many vernacular names: the “Sucurucu”, the Brazilians believe, can extinguish fires, and will suck the milk from cows and sleeping women; the “Matabuey”, the Costa Ricans say can kill oxes; “Cascabel muta” inspired Carolus Linnaeus, the founder of modern biological nomenclature, to name it Crotalus muta, the silent rattlesnake. Early explores to the New World returned with fanciful accounts of this monstrous serpent laying waste to whole mule trains.

So impressed was Francois-Marie Daudin, a late 18th century herpetologist, that he assigned the bushmaster to its own genus, Lachesis, named after one of the three fates in Greek mythology: Clothos, the spinner of life’s thread; Lachesis, the drawer of lots, chose the length of one’s thread; and Atropos made the final cut. Lachesis muta, the silent arbiter of one’s fate!

So much for the myth: what of the real bushmaster? Well it is a truly remarkable snake in every way: reported to grow to 4.25 meters, the bushmaster is by far the largest viper in the world. Only the king cobra of Asia and the common taipan of Australia, both members of the cobra family (the Elapidae), oust it from the title as largest venomous snake in the world. It is the only viper in the New World to lay eggs (oviparous); all the others bear live young (viviparous). And, what few records there are of bites from this snake, suggest an 80% mortality rate among humans, making the bushmaster the most deadly snake in the Americas.

The bushmaster is rare, though – perhaps fortunately so! Its narrow habitat requirements confine the bushmaster to undisturbed, lowland primary rainforest. In this it differs from its soul mate in terror, the terciopelo, whose cosmopolitans habitat tastes bring it regularly into close proximity to people. So for all its fame, the bushmaster is rarely seen, whereas everybody is familiar with the terciopelo.

Bushmasters, like terciopelos (and all other vipers), rely on stealth and camouflage to surprise and ambush their prey. But, unlike the terciopelo, the bushmaster has a very specific dietary habit: both young and adults eat almost exclusively mammals, from mice to rats, agoutis and opossums. Adult terciopelos will take rats and opossums, in addition to frogs and lizards. But their young feed only on lizards and frogs.

The bushmaster and all of its New World cousins belong to a sub-division of the viper family, the Crotalinae, or pitvipers. They are so named because they posses a pair of pits, one on each side of their heads, between their nostrils and eyes. These pits function as infrared heat sensors, enabling these vipers to detect the body heat of their prey. Indeed, these pits are extremely sensitive to temperature changes (to small fractions of a degree) and in effect function as a second eye, allowing these remarkable snakes to see the world in the infrared spectrum as well as in the visible spectrum of light.

The venom of the bushmaster, and all other vipers, is a complex cocktail of toxic compounds. Its primary function, like the venom from the other main group of poisonous snakes, the cobras and allies, is to immobilize prey. Cobra venom is termed a neurotoxin, and achieves this effect by arresting the nervous function of its prey. Viper venom, termed a haemotoxin, achieves the same result by disrupting the circulation system, among other things. But viper venom has another trick up its sleeve!

All snakes eat relatively large prey, whole. And this presents them with a problem: how to digest the animal before it rots from within. Most snakes solve this problem by possessing powerful digestive systems. But vipers have found a less costly solution: they inject venom that not only kills the prey, but also begins the process of digestion before the prey is even ingested. This digestive quality of viper venom causes rapid tissue damage, however, and makes bites from these snakes particularly nasty. Recovery from a cobra bite will leave little or no visible evidence of the incident. Not so with a viper bite: at best one will be left with unsightly local scaring as a reminder. At worst, amputation!

Drop for drop, the venom of the bushmaster is not as potent as many other venomous snakes, but it is the shear volume of venom and the depth to which its long fangs can inject it, that makes this pitviper so potentially dangerous.

The bushmaster ranges from Nicaragua through the rest of Central America into Colombia and Ecuador in the west, and down into Brazil in the center and east of South America. Within its range, four sub-species are recognized. One of these four sub-species, Lachesis muta melanocephala, is confined to the Osa. It differs from the other sub-species by, among other things, the black coloration of the top of its head – it is known locally as the “Plato Negro”. Another difference is in the plato negro’s temperament. Researchers at Costa Rica’s anti venom institute, the Instituto Clodomiro Picado, have informed me that the Osa’s bushmaster is the most aggressive of them all – the few locals who encountered this snake will attest to this – and responsible for more casualties here than the other sub-species of bushmaster elsewhere in the country.

Ground dwelling, ambush-hunting snakes like the bushmaster, the terciopelo and the boa constrictor rely on cryptic coloration of rhomboidal markings for concealment, both to catch their prey and to hide from predators. When disturbed, these species will remain still, at least initially, relying on their camouflage for protection. Large, active hunting snakes – all non-venomous, or only mildly venomous! – like tiger rat snakes, sipos, mussuranas and cribos react to disturbance by fleeing rapidly. These snakes are also more uniform in color, or at least lack rhomboidal patterning. So if, like me, you delight in the esoteric sport of snake-catching here is a rule of thumb: fast moving, uniformly colored or striped snakes that live on the ground, grab immediately; banded snakes, or rhomboidally colored snakes that remain coiled when approached, hesitate initially, they may be poisonous. This rule falls apart for arboreal snakes, however, so it is wiser to leave all snakes alone!

In appearance, both the bushmaster and the terciopelo look mean and menacing, and some say even malevolent. The terciopelo, being a lance-head pitviper, has pronounced triangular-shaped head. And, as its name implies, the terciopelo has a velvet appearance to its skin. The bushmaster in contrast has a more rounded, rattlesnake-like head, and skin that is covered bead-like scales. The terciopelo, it is said, caries with it an aura of neurotic unpredictability; the bushmaster, an aura of calculated malevolence. Few animals for me embody the spirit and mystique of wild, pristine rainforest like the majestic bushmaster.

A Postscript

Since writing this article, new information about the taxonomic status of the infamous bushmaster has come to my attention. As indicated above, the bushmaster was considered to be one species, with several geographic sub-species. Recent biometric evidence, however, has raised the level of three of these sub-species to specific status: The South American species, Lachesis muta, the Central American bushmaster, L. stenophrys, and the black-headed bushmaster of the Osa, L. melanocephala.

Mike Boston is a biologist, wilderness expedition guide, and the president of Osa Aventura. You can contact him at at [email protected]

The Sloth

Osa Safari: The Sloth
by Mike Boston of Osa Aventura

Brown-throated three-toed sloth

Brown-throated three-toed sloth

High upon people’s lists of ‘must sees’ when visiting Costa Rica is the sloth. The sloth has an intrinsic charm, which people find endearing, rather like the koala bear of Australia. It is benign, odd looking, yet cute, and hangs upside down from branches. But let‘s face it; the sloth is not the most exciting animal in the Neotropics! Nonetheless, behind its rather boring façade lies a very interesting creature indeed.

If any animal were to symbolize the uniqueness of the Neotropical fauna it would be the sloth. It belongs to the oldest extant order of placental mammals to have originated from South America, the Xenarthra (formerly known as the Edentata) – an ancient group that, incidentally, also include the anteaters and armadillos. This once large and diverse order included giants like the huge armadillo-like glyptodont, and giant ground sloths, some as much as four tons in weight. Incidentally, these giants migrated north from South America once the Panamanian formed, 2.5 million years ago, and were a conspicuous component of the once impressive mega fauna that roamed the forests and plains of both continents. Their extinction, a mere few thousand years ago, coincided with the arrival people to the New World!

The Xenarthra evolved and radiated in isolation for over 50 million years on the South American continent into ten familial lineages. Today, alas, only four of those familial lineages remain. Curiously though, two of these families are represented by the sloths – the anteaters and the armadillos represent the remaining two families.

In the forests of Central America live two species of sloth: the Brown-throated Three-toed sloth (Bradypus variegatus) and Hoffmann’s Two-toed Sloth (Choloepus hoffmanni). Although both species look superficially similar, current taxonomic opinion considers them to be sufficiently different to warrant their inclusion in separate families: the former is placed in the family Bradypodidae, the latter in the Megalonychidae.

Hoffman's two-toed sloth

Hoffman’s two-toed sloth

The smallest of the two species and the most commonly seen, is the Brown-throated Tree-toed Sloth. An adult may weigh up to 4.5 kgs (10 lbs) and has long, shaggy fur that is grizzled gray in color. The Brown-throated Three-toed Sloth has a cute, smiling face, with a small dark snout, a dark mask through the eyes and whitish fur on the forehead. As its name suggests, its throat is brown and it has three claws on its forelimbs. Hoffmann’s Two-toed Sloth is larger; adults can weigh up to 6 kgs (13 lbs). Its fur is dull brown in color and its snout is rather pig-like. But, the main distinguishing feature separating it from its smaller cousin is the presence of only two claws on its forelimbs. In both species their coloration can take on a greenish hue. This is due to algae coating their shaggy fur.

The word sloth is synonymous with laziness. Indeed, the local name for the sloth, ‘perezoso’, is used to describe a person of a rather lethargic disposition. However, there is a reason for the sloth’s apparent laziness: their diet. Both species dine exclusively on leaves. While the rainforest may appear to be one huge salad bowl for sloths, leaves are in fact hard to digest, low in nutrients and laced with toxins. To subsist on this low quality diet, sloths have undergone many physiological and behavioral adaptations: they are selective about the leaves they eat, often choosing younger leaves that are easier to digest; they digest leaves with the aid of bacteria in large, fermentation stomachs, similar to those of the ruminants; and sloths conserve their hard-won energy by being lethargic. Indeed, sloths maintain a low metabolic rate, almost akin to reptiles. Maintaining a high, constant body temperature, as do mammals and birds (endotherms), is extremely costly metabolically. Sloths are perhaps the most reptile-like mammals in their thermoregulatory behavior: they depend greatly (though not exclusively like reptiles) on basking in the sun to raise their body temperature. They are thus partial exotherms.

Little is known about the reproductive habits of Hoffmann’s two-toed Sloth. Because it is generally more common and more diurnally active than its larger cousin, the habits of the Brown-throated Three-toed Sloth are better known. This species reaches sexual maturity at about three years of age. Females produce one offspring per year after a gestation period of six months. The young remain with its mother for about one year before seeking its independence. Mortality rates can be high for sloths during their first of life, but once passed this vulnerable stage they can live to be 20 to 30 years in the wild. The main predators of sloths are harpy eagles and the larger cats.

Another behavioral curiosity of sloths is their habit of descending from the forest canopy once a week to defecate. No satisfactory explanation has been proposed for this odd behavior, but it does suit to veritable entourage of insect dependants that live in their fur. Several species of moths and beetles live exclusively in association with sloths. These insect scurry from the fur of the defecating sloth and lays their eggs on its dung. They then scurry back aboard the sloth before ascends again! The nature of the association between these insects and the sloth is not clear.

Despite the high population density of sloth in rainforest canopies, they can be difficult to see. Sloths will feed on many different species of trees, with individuals showing preferences for certain tree species. However, the Cecropia trees do seem to be a favorite among sloths, and it is in these rather open trees that sloths are most commonly seen.

One last curious fact about sloths is their dentition: their dental compliment does not include incisors and canines, and their remaining teeth, molars and premolars, lack enamel. Hoffmann’s Two-toed Sloth has what appear to be large canine teeth, but these are in fact enlarged premolars.

Sloths are tenacious survivors and are not in any immediate danger of extinction. So long as our Neotropical rainforests are conserved, even if only in National Parks and reserves, these curios of the natural, the sloths, have a secure future.

Mike Boston is a biologist, wilderness expedition guide, and the president of Osa Aventura. You can contact him at at [email protected]

A Night in the Jungle

Tales from the Jungle: A Night in the Jungle
by Kenneth Barnet

I was lying on my back, in a cabin, in a rainforest, on the Osa Peninsula of Costa Rica. It was 3:15 am.

There was nothing dry anywhere in my cabin. Nothing. ” Urg,” I said out loud as I removed a three inch cockroach from my lower lip. Never mind the mosquito net, it easily climbed through the hole in the foam mattress and right into my supposedly secure sleeping enclosure.

Yea right. I had to almost laugh at even having a mosquito net dangling over my head. Plus, I had kicked it and tore it off the posts twice already.

Why wouldn’t the bugs like my bed?, after all it was soaked in salty sweat and about 100 types of tree saps. Not to mention the particles of plants all over my skin, and um, um, all the human fluids formerly deposited on my gray/black mattress that just really, really, wasn’t a mattress anymore.

I couldn’t have sweated anymore, at least I thought I couldn’t. Because about that time my body again swelled up and I felt the fluids dripping off of my chest and off of my stomach and on to the sheet. I had to keep soaking up the sweat in my belly button with my T-shirt.

“Bring cotton sheets, light cotton,” Mike Boston had told me. Yea right, they really help.

I saw my wife open her eyes and look at me, “Are you okay?,” she said.

“Yes,” I replied. “Can humans die from sweat, I mean, not from sweating, but from being IN sweat?”

“Go to sleep.”

It’s just wonderful lying on soaking wet cotton sheets on top of a hazardous waste platform. Just wonderful. What were the alternatives? Sleeping among some three horned Katydids and baby fer-de-lances with the possibility of getting crapped on by kinkajous?

Hum. I tried to get into a deep sleep but it proved fruitless. I heard someone cut a huge fart in the room next door, and then, I heard the splash of water. Someone had midnight diarrhea. And the bathroom was nearby. It began to smell like a porta-potty at a NFL game. But then another fart came from another direction.

Man, were the howler monkey’s farting? I shouldn’t have mentioned howler monkeys to my own mind’s eye… cause it was getting to be 3:30 am, and they were about to start. I rarely slept through the howler monkey cacophony. But it was just a bit better, then hearing some farts and splashing water.

I couldn’t wait to get up and change into my other smelly wet T-shirt. We were going to hike up the Claro River this day, to find dart frogs. Was I among the border line insane I wondered? I immediately thought that if I had some Xanax on me down here I could have slept right through the night, and probably have had cockroaches in my nostrils, or at the very least a land planaria boring through my urethra into my bladder. But, I also thought that it wouldn’t be fun hiking in the morning with a benzodiazapam hangover. Just not cool.

I had to notice the tree vipers, and I had to have the power to yell at Dave when he made everyone wait on the path for the 30th time while he tried to get the perfect picture.

I love this place. Really. Crap, I let out my own, huge, loud fart. I heard someone giggle down the hall.

Kenneth Barnet writes this little humourous anectdote about his night at Sirena Station in Corcovado National Park

Jewels of the Forest

Osa Safari: Jewels of the Forest
by Mike Boston of Osa Aventura

Many animals, from birds to insects, could justly tender a claim to the accolade of ‘jewels of the rainforest’, but none perhaps, with the deservedness of the dendrobatids. These tiny, often colorful frogs, bedecked in greens, reds, blues and yellows, are among the most striking and gaudy denizens of our rainforests. They are as familiar to us as the poison-dart frogs (family: Dendrobatidae), found throughout the rainforests of the New World.

Poison Dart Frog
Poison Dart Frog

Of the 170 species of Dendrobatidae thus far described, only 65 are gaudily colored and produce potent skin toxins – these are the true “poison-dart frogs”. The remaining species are more somberly colored in hues of browns and creams and lack potent skin toxins. This fact confirms, incidentally, that the true poison-dart frogs use bright coloration to advertise their toxicity to potential predators. I shall, therefore, refer to the family as whole as the “dendrobatids”.

The name “poison-dart frog” is derived from the dependence of native Indians in the Choco region of western Colombia upon the toxic secretion of these frogs to anoint their blow-gun darts. Only two or three species of dendrobatids were used in this practice, themost notable being Phyllobates terribilis, the golden poison-dart frog. This striking little frog, entirely bright golden yellow in color, secrets from its skin some of the most potent toxins (batrachotoxins) known man. One frog, it has been estimated, can produce enough toxin to kill 20,000 mice – or 10 people

Poison Dart Frog
Poison Dart Frog

This hyper-toxicity is the exception to the rule, however. Although all of the colorful dendrobatids do secrete an elaborate cocktail of toxins from their skins, most pose little threat to us. These toxins are designed to primarily to make the frogs unpalatable to predators – when you think of it, this advantage is lost if a naive predator dies from its first encounter with one of these frogs; it will have learned nothing! Like many butterflies (the monarch for example), these colorful dendrobatids advertise their unpalatability to predators through gaudy, easy to remember, coloration. In consequence, these engaging little frogs go about their business on the forest floor with an air of nonchalance, confident in their invulnerability, and make only token efforts to flee when they are encountered.

The skin toxins of dendrobatids (and, indeed, other frogs) have been the subject of a considerable amount of research in recent years – research in which I, myself, have participated with Queen’s University of Belfast. Many components of the cocktail of toxic secretions these frogs produce have been found to have useful medical applications, anticancer and antibacterial compounds among them. However, one compound isolated from Epipedobates tricolor, the phantasmal poison-dart frog from Ecuador, has caused a sensation in the pharmaceutical world. The compound, called Epibatidine, is found to be 200 times more effective as a painkiller than morphine – the most potent analgesic hitherto known. Unfortunately, Epibatidine is also toxic, but research is under way to manipulate its chemical structure to remove the toxic component while retaining its incredible analgesic properties.

So much for the toxicity of the dendrobatids, what about their behavior and ecology? Well, unusually for frogs, dendrobatids are diurnal in habit. They forage by day among the leaf litter of the forest floor for their insect prey. A major component of the diet of the colorful dendrobatids is ants, from which, it is assumed, they derive their toxins – an assumption based on the fact that captive dendrobatids, fed on non-ant prey, soon loose their toxicity. Female dendrobatids lay only a few eggs, from four to twelve, in moist locations amongst the leaf litter. The eggs are guarded vigilantly by either the male or the female (depending on the species) until they hatch, about two weeks later. The guardian will, during this period, moisten the eggs frequently, either with their urine or moisture carried on their skin from a nearby water source.

The guardian (male or female depending on the species) will then carry the tadpoles on its back and deliver them to a small water reservoir, in a tree hollow or a bromeliad, high among the trees – a characteristic peculiar to the Dendrobatidae. There the tadpoles feed on organic detritus or insect larvae (again, depending on the species) until they metamorphose, two to tree months later. Some species of dendrobatids, where the female is the guardian, periodically lay unfertilized eggs in the water reservoirs for their tadpoles to feed on. This degree of parental-care is quite unusual among frogs!

Costa Rica is home to eight species of dendrobatids, five of which occur in the Southwest Pacific region and the Osa. And two of these species are endemic to the Southwest Pacific region: Dendrobates granuliferus, the granular poison-dart frog, and Phyllobates vitttatus, the golfodulcean poison-dart frog.

Our largest dendrobatid, Dendrobates auratus, the green and black poison-dart frog, is also the most widely distributed. It is found from Southern Nicaragua through to Southern Panama, and occurs on both versants of Costa Rica. Dendrobates pumilio, the strawberry poison-dart frog or blue-jeans frog, is common along the Atlantic versants of southern Nicaragua, Costa Rica and Northern Panama. Its red body and blue legs, typical of the Costa Rican populations of this species, closely resembles the color form of the granular poison-dart frog of the Osa and adjacent areas. Similarly, Phyllobates lugubris, the lovely poison-dart frog of the Atlantic versant of Costa Rica and Panama, is replaced by its sibling species, the golfodulcean poison-dart frog endemic to the Osa area.

The remaining three species of dendrobatid found in Costa Rica belong to genus Colostethis, drab-colored members of the Dendrobatidae. They are called rocket-frogs from their habit of launching themselves, head long into streams when disturbed. Rocket frogs are among the most common dendrobatids in our forests. The high-pitched “peet – peet – peet” call of Colostethus talamancae is a common accompaniment to anyone hiking through Corcovado.

Dendrobatids, especially the colorful poison-dart frogs, are in high demand among hobbyists in Europe and North America. This is a two-edged sword, however. On the one hand their high commercial value has put a strain on wild populations from over-collecting. But on the other hand, these hobbyists are successfully breeding many species of dendrobatid in captivity, thus maintaining captive populations and preserving them from their main threat, habitat loss. Amphibians are on the decline world wide for reasons that are not entirely clear, but go beyond habitat loss. Global warming, ozone depletion, desertification, insecticides, air pollution and even fungal diseases spread by herpetologists have all been proffered as contributing factors. So concerned are conservationists that The International Union for Conservation of Nature (IUCN) has formed a special ‘Declining Amphibian Populations Taskforce’ to investigate the problem.

Surely our majestic rainforests would be all the duller were it not for these jewels to adorn their splendor!

Mike Boston is a biologist, wilderness expedition guide, and the president of Osa Aventura. You can contact him at at [email protected]


Tales from the Jungle: Snakes
by Mike Boston of Osa Aventura

Snakes are my passion – or one of them! They were my father’s passion too, when we lived in Trinidad and Tobago. He bequeathed his passion to me, as I have done to my daughter. I have been associated with snakes all of my life: I have kept them, bred them, caught them, rescued them and released them; they have excited me, scared me, embarrassed me, bitten me and shit on me!

Snakes stirs us all, deeply. We have an innate fear of them, indeed, so does much of the animal kingdom. Snakes hold this revered position by virtue of the venomous members of their ranks. Our culture, its myths and legends abound with references to snakes. They are revered and reviled wherever they occur, and often slaughtered as a result. Our combined feelings of revulsion and fascination towards snakes could hardly be more eloquently articulated than by the words of Alexander Skutch, a passionate birder and coauthor of A Guide to the Birds of Costa Rica. I quote: “The serpent crams itself with animal life that is often warm and vibrant, to prolong an existence in which we detect no joy and no emotion. It reveals the depth to which evolution can sink when it takes the downward path and strips animals to the irreducible minimum able to perpetuate a predatory life in its naked horror. The contemplation of such an existence has a horrid fascination for the human mind and distresses the sensitive spirit.”

I don’t share Skutch’s feelings, though most of us do. I hold snakes to be one of the most beautiful, precise and lethal carnivores ever to have been sculpted by evolution. Ideed, they are the most successful terrestrial carnivores ever to have lived on Earth, and out number all other terrestrial carnivore species many times over.

Morphologically, they have nothing in excess. Snakes are without limbs, ears and eyelids – but as though to be compensated, evolution has equipped each snake with two penises! However, despite their morphological frugality (or perhaps because of it!), snakes move and hunt in any realm with pernicious economy.

The most commonly expressed fear by people I take into rainforests of Corcovado concern snakes. The fear of snakes expressed by two women I was about to take into Corcovado was uncommonly intense, however. In fact, they were about to cancel the tour when I told them that I don’t carry anti-venom with me. I barely managed to persuade them to go when I exclaimed “don’t worry, you very rarely see snakes!” The women were only partially convinced when we stet off by taxi to Carate, the southern gateway to Corcovado. The mischievous side of me prayed we would find a snake!

Whether it is a figment of my imagination or not, it certainly seems to be the case that there is an inverse relationship between a persons desire to see snakes and their likelihood of seeing them. I seem to find more snakes when in the company of those who dread them most! Never was this paradoxical phenomenon better illustrated to me than in the events that were about unfold as we set off to explore Corcovado.

“You never see snakes, huh!” remarked one of the women as the taxi driver pointed out a large, electric blue keel-backed racer, Chironius carinatus, on the road a short distance ahead. I just can’t resist catching snakes and, despite the protests from the women, I burst out of the taxi and ran towards the snake. Keel-backed racers are fast diurnal hunters, with large eyes and keen vision. They are wary snakes, and one cannot afford finesse when attempting to catch them. So I lunged at the snake, just as it was about to disappear into the undergrowth, and seized it by the tail. The snake turned and struck at my face, but with reflexes of a prize boxer I dodged, and the snake missed.

I now had six feet of angry snake suspended from my grasp. Meanwhile, protests from the taxi were reaching fever pitch: “No, Mike!” “please don’t, Mike!”

Me with a boa on the road to Carate

Me with a boa on the road to Carate

The snake then bit my knee, released and struck again at my chest. In the process of getting the snake into a more manageable position it bit me several times more on my left arm. With the snakes head now under control and my knee, chest and arm oozing rivulets of blood, I approached the taxi. I had a huge grin on my face – my prayers were answered, I thought!By the time I reached the taxi the snake had settled down in my gentle grasp. The expressions on the women’s faces were ones of total disbelief. They were aghast and speechless. My enthusiastic dissertation on snakes, extolling their abundant virtues, went largely unheard!

I released the snake, wiped the blood from my arm, chest and knee, and jumped into the taxi. The women were amazed that I was still alive, and examined my bite wounds minutely, and repeatedly. They said I was a complete lunatic and begged me to desist from such activities lest I die, and leave them abandoned in the jungle. But, of course, I didn’t!

In fact, I caught several more snakes during the course of our explorations of Corcovado over the coming three days – more than normal! But, their regard for snakes gradually transformed from one of dread to fascination. Indeed, towards the end of our tour, the women were searching for snakes as enthusiastically as me.

“You lied to us!” one of the woman exclaimed. “Yes, you did!” the other agreed, before they both burst into laughter over a farewell drink. “We had a great time though!”


This curios affinity between snakes and ophiophobes was evident on another occasion, while I was working at Mapache Lodge on the Rio Sierpe. Two Canadian couples arrived for a three-night stay at the Lodge, bent on exploring the Osa’s rainforests. There was one problem, though: one of the women was terrified of snakes.

Our frequent forays into the jungle were for her a nightmare. Every time we returned to Mapache Lodge her relief was palpable. She felt safe there!

However, her illusion of safety in the confines of the Lodge was shattered on the second evening while they were sitting around a table on the verandah. I stood beside the table talking to them when the husband of the woman said, in a matter-of-fact way: “ I think you had better move, darling!”

Directly above her head a common tree boa, Corallus hortulanus, was dangling from the rafters, stretched vertically, intent on reaching her head. The boa’s intent was ultimately to reach the floor, but it was funny that it chose her head out of the five that were there to achieve its objective.

It amuses me how perspectives among us can be so different in a given circumstance. I see the jungle and its creatures, especially snakes, as things of beauty and fascination. The perspective this woman held could hardly have been more different. This incident reinforced in her the conviction that jungles are hell, caldrons of serpentine nightmares. She slept little that night and insisted on leaving the next day. A day early!


One of my most embarrassing incidents involving snakes was when I took a pleasant and modest Italian couple on a night tour of the Rio Sierpe. This river is a superb venue for nighttime, wildlife forays as its waters and banks team with crocodiles, caimans and snakes, the eyes of which glow red in a flashlight beam.

Julio, the owner of the lodge at which I then worked, steered the boat diligently between the rafts of water hyacinth that drifted down the river. Armed with a one million candlepower spotlight, I scanned the water and banks for telltale eyes. I had just released a small crocodile, which I had caught to illustrate to the Italian couple the virtues of these delightful beasts, when I noticed red eyes from vegetation on the nearby bank. I knew that it was a snake, and in all probability a common tree boa.

With my spotlight fixed on the spot, Julio docked the boat, bow first, on the muddy bank. I gave the spotlight to the Italian woman. She illuminated the unfolding scene for her husband to video. Armed with my flashlight I jumped ashore and approached the snake. It was a particularly large common tree boa. Gently, I retrieved the snake from the low vegetation. It was a two-handed operation, though, and I had to hold my flashlight in my mouth. With the boa entangling my both arms, I headed back to the boat. The Italian couple excitedly videoed the drama.

However, mounting the bow of the boat, with both my arms occupied, proved difficult. It was when I raised my leg to attempt the operation that my trouser snake made an untimely appearance from the leg of my shorts!

A diplomatic silence pervaded the air. With a video pointed at me, and the power of a million candles illuminating my embarrassment, I could do absolutely nothing but continue to mount the boat.

Having done so, I attempted to draw attention to the snake while simultaneously maneuver my John-Thomas back to its proper, more seemly position without hands. Having achieved partial success in this matter, and having delivered my talk extolling the virtues of the lithesome beast occupying my both arms, I turned, knees together, and delivered the snake back from whence it came. Diplomacy was maintained, and nothing was said. I prayed that the video wouldn’t be screened on television at a later date, on one of those most funny home video shows!


Rescuing a common tree boa near Sierpe village

Rescuing a common tree boa near Sierpe village

While living at Mapache Lodge, some distance up the Rio Sierpe from the village of Sierpe, I took it upon myself to rescue snakes from the machetes of ohiophobic locals. I received considerable cooperation, particularly from Don Marino from La Palma. He presented me with many fer-de-lances caught by his farm workers.

Journeying to La Palma from Mapache Lodge to collect Don Marino’s offerings involved a boat journey, two bus journeys and an overnight stay in Cabinas at La Palma. I often muse over what the reactions of the drivers and passengers would have been had they asked me what I was carrying aboard the buses on my frequent journeys!

For some reason, my appeals to the local people to spare snakes, and allow to save and release them, yielded mostly fer-de-lances. I would keep these snakes at Mapache Lodge for a period before releasing them. My collection grew!

At one point I had fourteen snakes, seven fer-de-lances and seven assorted species, variously acquired. I had at this time been making plans to set up a snake breeding facility at the lodge, and had been in consultations with the Clodomiro Picado for permission to do so. They were very supportive towards the project, which left me only to deal with the paper work. I, therefore, kept the snakes now in my possession to stock my proposed facility.

Feeding these snakes was a problem. I acquired three pairs of laboratory rats as a solution, and prepared to breed them to satisfy the growing appetites of my burgeoning menagerie. I waited, and waited, but the rats refused to breed. Meanwhile, I had only an infrequent and inadequate supply of trapped rodents from the Lodge’s kitchen to satisfy the appetites of my snakes. So I now found myself in the annoying situation of having six stubborn, celibate rats and fourteen hungry snakes. In a fit of pique I released all of my snakes except one, an injured boa constrictor, and verbally threatened the rats with execution. (I like rats, and having to feed them to my snakes is one the aspects of snake husbandry I dislike most.)

It was not long, however, before the rats started breeding. I now found myself in the equally annoying situation of having one well-fed boa and a growing surplus of rats. A snakes’ economy also applies to its diet. Being heterothermic, snakes require a mere fraction of the food that a homoeothermic bird or mammal of equivalent size requires. My boa’s appetite thus couldn’t keep apace with my rat’s procreativity. My problem was by this time further compounded by the fact that the Lodge was due to close and that I was about to leave. The snake-breeding project was shelved and I was now faced with the prospect of having put down over fifty rats, a prospect I didn’t relish.

A solution presented itself in the form of a forty-pound boa constrictor. Henry, the Lodge’s caretaker, and his brother had come across this boa while working on their father’s farm. They had ushered it into a cage for me to collect. With delight, I set off with Henry by boat to his father’s farm.

Approaching twelve feet in length, this boa was one of the largest I had ever seen – and one of the meanest too! It retracted its head into the strike position and hissed menacingly when I approached its cage. It stuck violently at me, but missed. Quickly, I grabbed the boa behind the head and proceeded to draw it from the cage. It’s hissing intensified. To control this large snake I had to subdue its head in my right arm, its’ hind end with my left arm and drape the bulk of its’ body around the back of my neck and shoulders. Unable to bite me, the boa discharged its next line of defense: shit! It delivered a payload of several pounds of its fetid turds down my chest and legs. The smell was horrendous!

Henry and I installed the boa at Mapache Lodge, and left it for a few days to settle into its new surroundings. Once settled, I began delivering rats to it. The boa ate them without hesitation, six at a sitting. Over the next month this boa gained considerably in weight as it disposed of all my rats. I released it, along with the convalescing boa, and left Mapache Lodge.


Being bitten by a snakes, large boas, pythons and venomous species excepting, is really quite an innocuous experience. Despite their formidable reputations, snakes are light boned and fragile creatures. Because snakes eat relatively large prey whole, the bones of their jaws are necessarily light, designed to disarticulate during swallowing. Lined with needle-like teeth, the jaws of snakes function to hold onto rather than crush prey. Therefore, snakes do not have a powerful bite.

A good friend of mine, Philip Davison, and I took being bitten by animals to an art form. We met at university in Portsmouth, southern England, as a result of our common interest in reptiles. Between us, we kept veritable menagerie of snakes and lizards. Frequent bites from our reptiles and our macho boastings about them conspired to engender spirited of competition between us. Eagerly we would place our fingers in the jaws of any reptile that was willing to bite them.

Consequently, we both lost our fear of being bitten. Although we reserved a respect for venomous snakes, and never deliberately allowed ourselves to be bitten by one, that respect was starting to diminish. Meanwhile our catalogue of bites was growing along with our boasts: I had the bite from a powerful three-foot tegu (a large South American lizard) atop my list of credits; Philip had matched that with the bite from a nine-foot reticulated python.

One day we both added baby European adder bites to our lists. Some time previous we had caught twenty-four adult adders, and from those had kept three gravid females. On that day, the adders produced between them about thirty babies. They were the most delightful little snakes, and mean too. We bagged the babies and prepared to release them. But first, we could not resist putting our hands into the bag to let the mass of babies bite us – which they did with gusto! The experience was like putting our hands into a bunch of stinging nettles!

Some days later, Philip greeted me with big grin on his face. He couldn’t wait to tell me that one of his cane-break rattlesnakes had bitten him. Fortunately for him it was a dry bite, causing only a little localized swelling. He was so proud of his wound and displayed it to every one. He knew that it would be a hard act for me to follow. He was right!

Today, some twenty-five years hence, we find ourselves together again on the Osa Peninsula, still indulging our passion for reptiles. We meet frequently on reptile forays, and often handle coral snakes and the lance-head vipers of the area. But to this day, Philip can still boast that he has been bitten by a more dangerous reptile than has ever bitten me.


On night tours, I like to demonstrate to my clients the amazing alarm call of the smoky forest frog, Leptodactylus pentadactylus. This large frog emits a loud series of shrieks when captured, reminiscent of a crying baby. It has been speculated that this alarm call, emitted naturally when seized by a predator, is meant to attract other predators to the scene. If a scuffle between the predators then ensues, the frog may be given a chance to escape.

The likelihood of this speculation being true was suggested to me recently in Corcovado Park. I had brought three people on a canoe trip up the Rio Sirena, an awesome river that flows from the Corcovado lagoon to the sea near Sirena Station. The Rio Sirena teams with fish, including huge snook and snapper, which support a healthy population of bull sharks and crocodiles – I have encountered bull sharks several miles up river! It is also a favorite with tapirs, which spend a good portion of their time swimming in the river and browsing on vegetation from along its banks. A conoe trip along the Rio Sirena can be very rewarding to the keen adventurer and naturalist.

About three miles up river, the Rio Pavo is joins the Rio Sirena. From this point onwards, the Rio Sirena changes in character. Its flow becomes more sluggish, lush growths of water vegetation sprout from its bed and rafts of water hyacinth cling to its banks. Shoals of curious snapper swarm in the crystal clear water, and often emerge from the among the water plants to follow our canoe. Northern jacanas, purple gallinules, anhingas, Muscovy ducks and other water birds abound. So do crocodiles!

It was on this stretch of the Rio Sirena, while savoring the natural ambience from under the shade of a large fig tree, that my fellow canoers and I heard a strange noise coming from the forest on the far bank. A first we paid the little heed to the noise, but its persistence began to draw our attention.

The noise was strangely familiar to me, yet I couldn’t put my finger on its identity. A jaguar or puma cub perhaps, I speculated. We grabbed our paddles and made our way the far bank to investigate.

Quietly, I got out of the canoe, ascended the bank and surveyed the scene. Perched on low vegetation, directly above the source of the noise, were two common black hawks, looking down intently. As I approached they flew off revealing a huge snake trying to swallow a large smoky forest frog, rump first. The snake, a black-tailed cribo, Drymarchon corais, was perhaps the largest colubrid (typical snake) that I had ever seen. It was now that I realized why the noise seemed familiar to me. I am well acquainted with the alarm call of the smoky forest frog, but hearing it out of context, namely during the day, had confused me.

I beckoned the others to come, and together we looked on in amazement. The huge cribo wrestled with the frog, trying in vane to swallow it, oblivious to our presence. The smoky forest frog shrieked repeatedly while struggling to get away. The scene was a gruesome one and I fought against helping the hapless frog. Though, I did take the opportunity of stroking the cribo while its mouth was occupied. It nudged my hand away with a coil of its body, and continued its task. We left and let nature take its course.

The struggle between the two combatants had been going on for ten minutes or more when we arrive, and continued until we were out of earshot, some fifteen minutes later. The cribo was too large for the common back hawks to deal with, but I wonder what would have happened if the racket had attracted the attention of one the large cats? Would the cribo have fared so well? I doubt so. In that scenario, perhaps the frogs shrieking could have saved its life!

To be continued……

Mike Boston is a biologist, wilderness expedition guide, and the president of Osa Aventura. You can contact him at at [email protected]

Jaguar Encounters

Tales from the Jungle: Jaguar Encounters
by Mike Boston of Osa Aventura

I love Costa Rica, its people, and its rich and varied nature. But, I especially love the Osa Peninsula: it feels wild and remote – and it is; it possess a spontaneous and fickle charm which repeatedly confound ones expectations; and it has an intrinsic and seductive serenity, which conspire to beguile and impassion those fortunate enough to experience it. The Osa Peninsula has a way of enriching ones experience of life and ones memories of it. In the years that I have spent adventuring on the Osa, exploring its jungles, swamps, rivers and shores, encountering its wildlife and meeting its people, I have amassed a wealth of memories, and have many a tale to tell.


jaguar encounter

Jaguar encountered at Playa Corcovado
February 1997, at 4:00am
By Nelson Chenkin

To glimpse a jaguar is the ultimate prize of every eco-tourist to Costa Rica. Few expect to see one, and for those whose expectations are higher, disappointment is almost inevitable. But some visitors to Corcovado National Park each year, perhaps only one or two, are fortunate to see a jaguar – very fortunate indeed!

I number among those fortunate few. Indeed, in the years that I’ve been exploring the pristine forests of the Osa Peninsula, I’ve encountered two jaguars. And they were not brief encounters!

Jaguars are large cats, but enigmatic ones. They are the third largest in the world, and quite capable of killing people. Yet, jaguars have never had the man-eating reputations of lions, tigers and leopards of Africa and Asia. Authenticated records of jaguars having killed people in Central and South America are few. Why this should be so is not entirely clear, but it certainly makes one feel more at ease when entering the forests where jaguars haunt. However, my hitherto rather blithe regard for how dangerous jaguars can be was severely shaken on Christmas Day, 2001!

This day was the third of the 9-day `Multi-sport Tour of Osa’ that I operate in conjunction with Banana Adventure Tours. This multi-activity adventure thoroughly explores the Osa from Drake Bay, in the north, through to Carate, in the south. On this particular Multi-sport Tour of Osa I had seven, very enthusiastic participants. On Christmas Day, 2001, I took them on a hike to a remote area of Corcovado National Park, Playa Llorona.

Playa Llorona forms the northern portion of an eleven-mile stretch of beach that boarders the Corcovado Plane in Corcovado National Park. The Rio Llorona bisects the beach here, forming a tidal lagoon – home to large crocodiles and bull sharks! The lagoon gives way to extensive areas of mangrove swamp, including impressive stands of Pterocarpus officinalis, the sangrillo or blood wood.

Playa Llorona marks the northern extent of the Corcovado Plane. Immediately to the north and west rises the Los Planes Plateau, and the beach here gives way to cliffs and rocky promontories. Nearby, a beautiful waterfall cascades from the coastal cliffs of the Plateau, and offers refreshing relief to the hot a weary hiker.

Waterfall at Playa Llorona

Waterfall at Playa Llorona

The five-mile hike from San Pedrillo Rangers Station to Playa Llorona, across the Los Planes Plateau, takes one through some of the most majestic rainforests on the Osa. These forests abound with wildlife. En route my group of seven and I were obstructed by a large herd of fifty or more white-lipped peccaries. These feisty, pig-like beasts are perhaps the most dangerous mammals one is likely to encounter in Neotropical rainforests. If threatened, males will vigorously protect the herd. Their aggressive disposition is perhaps because white-lipped peccaries are among the favored prey of the jaguar.

The peccaries filed across the trail in twos and threes, initially unaware of our presence. The first one to get wind of us cracked its teeth in alarm, sending a ripple of agitation through the herd. A crescendo of teeth cracking erupted as the herd sped off. Several males stood menacingly on the trail, facing us and sniffing the air. The atmosphere was electric and the air reeked with the musty smell of these beasts. We were at a safe distance though, and stood our ground until the herd finally disappeared.

We arrived at Playa Llorona hot, but exhilarated. My group prepared to swim in the sea. I had a headache. So I retraced my steps back into the forest to a creek for water, to drink with my headache tablets – I have a hardy constitution and drink from the creeks to avoid having to carry water!

Some fifty yards or so back into the forest fringe of Playa Llorona I stood looking down upon the small creek that I had come to drink from. In the distance I saw a Jaguar. ‘Wow!’ I thought, ‘I’ve got to get closer’. Perceiving no threat from the cat, and fully expecting it to flee if it saw me, I began to sneak along the creek quietly, to get a closer. The jaguar must have shared my intentions, however, for when next I looked up it was staring at me from only 15 yards away.

To be in such close proximity to a large cat, without the intervention of bars for protection, is a sobering experience to say the least. For about five minutes we stared at one another fixedly, neither of us moving a muscle. My mind was racing, wondering how the hell I could get the others to see this incredible spectacle. However, I reckoned that it would not be possible, thinking that if I so much as moved the jaguar would run away. So I decided to savor this rare encounter to myself for as long as it lasted. At any moment, I thought, the jaguar would retreat. I was wrong!

I was reminded of the original purpose of my visit to the creek by the bitter taste of the headache tablets in my mouth. So I stooped to drink water from the creek. Suddenly, the jaguar crouched, lowered its ears, and began stalking me. ‘Goddamit!’ I thought, ‘you were supposed to run away!’

Never in my life have I been so exhilarated, so pumped with adrenaline and so concerned for my life. I knew that I would have no chance against a cat larger than myself. While stooped, I picked up two stones, preparing to stone myself out of this seemingly bleak situation in which I had now found myself.

I moved backwards, slowly. But the jaguar, with its eyes fixed on me, kept coming.

At what point it discontinued its advance, I can’t remember. For the next few seconds my fight-flight response was so heightened that it blanked my memory. My next recollection was running back to the beach, shaking and still clenching the two stones, to tell my group. All but one of them, Carroll-Anne, were swimming. In a frenzied state I said to her, “There’s a jaguar back there, come and see it!” Seeing my shaken state made her reluctant to follow.

The jaguar was still there upon my return, but had moved further into the forest. However, we both got a glimpse of it before it turned disappeared completely. I was glad to have a witness to my story!

In retrospect, I realize that my actions during this encounter with the jaguar were wrong, and had put my life in Peril. Initially I underestimated how perilous face-to-face meetings with jaguars can be. Under certain circumstances jaguars will attack people, sometimes fatally. Perhaps I had come close to providing those circumstances.

I was very excited, but not at all concerned when I stood staring at the jaguar, as I was sure that it would flee at any moment. Had I maintained my upright posture during the encounter, the jaguar may well have done so. But, cats are very impulsive in nature, and I realize now that by stooping to drink water from the creek I had invoked it’s hunting response. Furthermore, by moving backwards after it had begun stalking me, I had prolonged this response. If I had attempted to run away at this moment the jaguar may very well launched a full-blown attack on me. Realizing this at the time, I made absolutely sure that the jaguar was no longer pursuing before attempting to run back to the beach to tell the others.

This encounter on Christmas Day, 2001, is perhaps the best Christmas present I had ever received. I don’t regret behaving inappropriately in the presence of this large cat, for otherwise the encounter may not have been so exhilarating. My only regret, though, was not having a camera with me.

My first encounter with a jaguar came on a February night in 1997, while leading my `Osa Extreme’ adventure expedition through Corcovado National Park. It was on the fifth day of this 10-day adventure that we undertook the 16-mile hike from Sirena Station, in the center of the Park, to San Pedrillo Station in the north.

Aerial view of Playa Llorona in Corcovado National Park

Aerial view of Playa Llorona
in Corcovado National Park

This is an awesome hike. It is long and passes through some of the most remote and beautiful parts of Corcovado. From Sirena, the first 11 miles of this trail is all beach. This beach is the second longest on the Osa Peninsula and frequented by nesting turtles. Jaguars patrol this stretch beach nightly and prey on these turtles – their abundant pugmarks in the sand attest to this!

Intersecting this stretch of beach are three rivers: the Rio Sirena, the Rio Corcovado and the Rio Llorona, each equidistant from one another. The estuaries formed by these rivers are influenced by the tides, which make them fordable only at, or near low tide. This adds an imperative to the hike, therefore. An hour and a half before low tide is the soonest one can leave Sirena Station to ford the first River, the Rio Sirena. The second river, the Rio Corcovado, over five and a half miles away, does not usually present a problem as we arrive there just after low tide. But, unless one hikes the next five and a half miles quickly, the Llorona, the third river, is likely to be too deep to cross. Building a raft on which to float ones pack is often the only solution.

This hike presents two further problems. Firstly, the beach hike offers no shade. By day, therefore, one is at the mercy of the baking sun. I solve this problem by undertaking the hike at night. Bathed in either moonlight or starlight, hiking at night along this stretch of beach is awesome. Often, bioluminescence causes the breakers to flash green and the sand beneath our feet to sparkle.

The remaining problem faced on this hike is not so easily solved. These tidal estuaries are home to large crocodiles, and each incoming tide brings bull sharks, both of which feed preferentially at night. When crossing these rivers, one can only entrust ones fate to luck or whatever vestige of compassion these two infamous predators may posses. They certainly add spice to the hike!

On that February night in 1997, at 1:30am, I departed Sirena Station for the hike to San Pedrillo Station. With me were three rather nervous people, a middle aged American couple and a young Canadian woman. We had watched the bull sharks patrol the mouth of the Rio Sirena the previous day, and were now a little apprehensive about making the crossing. The eyes of three crocodiles glowed in our flashlight beams as we crossed, so we were quite relieved when made it safely to the other side. Two more crossings and 16 miles of beach and jungle now lay before us.

We do not need to use our flashlights on the beach, as the ambient light from the moon or stars is sufficient to illuminate our way. However, every 50 yards or so, I shine my flashlight ahead to look for wildlife. On previous occasions I had seen turtles, tapirs and ocelots, so I was quite optimistic about seeing animals as we began our hike along the beach. However, as time passed and nothing appeared, my optimism began to diminish.

Some two hours into our hike, just as my diminishing optimism was giving way to despair, I caught a glimpse of a pair of green eyes inmy flashlight beam, some distance ahead. ‘A jaguar’, I thought. I kept my flashlight fixed on the spot and picked up my pace. I felt sure that if it was a jaguar, it would disappear into the forest upon seeing my flashlight. So I was anxious to confirm my suspicions from the pugmarks it will have left in the sand.

The green eyes appeared in my flashlight beam again. Saying nothing to the others, I picked up my pace still more. The eyes appeared yet again!

As I approached I could make out two forms on the beach ahead. The green eyes again appeared, and as I neared I could make out the form of a jaguar crouched on the sand. Closer still, I saw that it was eating a turtle.

Aghast at the scene before me, I halted. I prayed that the jaguar would remain there until the others, now some ways behind me, arrived. I flashed my flashlight in their direction to spur them on. The jaguar turned its head to look at me again, its eyes gleaming in the beam of my flashlight, and then continued to feed on its kill.

We could scarcely believe our eyes as we stood about 10 yards away watching the jaguar nonchalantly eat the turtle. Our hearts pounded with excitement. The jaguar seemed only mildly perturbed by our presence, for it continued eating, glancing back at us quizzically only occasionally. Our flashlights had obviously confused it.

After feasting our eyes on this amazing scene for what seemed like ages, Nelson asked me if we could move closer, to within flash range of his camera – three meters! I asked Judith, his wife, and Tannis, the Canadian woman, to stay behind as Nelson and I inched forward. The jaguar looked at us again, and then continued eating once more. Nelson began taking photographs, his flash going off repeatedly.

The jaguar then left its kill and began approaching us. Our hearts pounded audibly. Like a seasoned photographer though, Nelson continued shooting. The jaguar then began walking past us, at which point Nelson ran out of film and had to make a quick change. He then continued shooting.

The expression on the jaguars face as it came towards us was one of curiosity, not malice. That was reassuring! In my experience I have found that animals are very often bemused by a flashlight. Being dazzled by the beam, and unable to see what lies behind it, animals often remain motionless or show little fear. It was certainly the case with this jaguar.

It continued to walk past us up to the forest fringe of the beach. There the jaguar lay down. Nelson, still shooting, and I followed it. By now its curiosity had turned to suspicion, and it rose and disappeared into the forest.

With our minds reeling from the encounter we now turned our attention to the ill-fated turtle. It was a Pacific green that had been intercepted by the jaguar before it had had a chance to lay its eggs. The jaguar, a relatively small female, had overturned the large turtle, delivering a fatal bite to its head. It then began eating into it from the hind flippers to get at the unlade eggs.

Crossing the Rio Llorona

Crossing the Rio Llorona

Nelson stowed his two reels of film as though they were made of gold, declaring that they were his most treasured possessions. Time was pressing though, and the tide rising. We had still to cross the Rio Corcovado, a short way ahead, and the Rio Llorona, some six miles away. We could talk of nothing else but the jaguar and our good fortune as we hiked. But, as we proceeded it was becoming apparent that we were not going to reach the Rio Llorona before it was too deep to wade cross.

We scoured the beach around the Rio Llorona for suitable materials from which to construct a raft. Fortunately, balsa logs, fishing floats and bits of rope were in copious supply. We began construction ever mindful of sharks and crocodiles. Beaming with pride at our handwork, we launched our raft, placing our packs on its deck. It floated admirably, and we began swimming across the Llorona pushing the raft. Judith and Tannis were very worried about crocodiles. Sharks concerned me much more. However, Nelsons only concern was getting his two roles of film across safely!

An adventure of a lifetime! This was the unanimous opinion of us all. Nelson promised to send me copies of his jaguar photographs as we bid each other farewell. I couldn’t wait. Some weeks later a package addressed to me arrived at my door. The photographs! However, I opened the package to find only one picture of the jaguar inside, and several shots of the hapless turtle. I was disappointed! In his accompanying note, Nelson told me that he must have been just outside the flash range of his camera, and that, with some enhancing, had managed to develop only one shot. My disappointment, however, was to a degree mollified by the knowledge that images of this jaguar encounter will for always be stamped on my mind.

To be continued……

Mike Boston is a biologist, wilderness expedition guide, and the president of Osa Aventura. You can contact him at at [email protected]