An American Naturalist: Expedition: Costa Rica Part I

Costa Rica: Search for the Fer de Lance

Part I

Expedition Overview

On this expedition, I travel to Costa Rica to search for a fer de lance, one of the largest viper species in Central and South America. My trek takes me from the dry rainforests of Palo Verde to the wet jungles of La Selva. In my quest to find a wild fer de lance, I discover many unique species that I've only read about in books. This is one trip for the record books. Join my journey as I search for the infamous and elusive fer de lance.

Palo Verde
One of my many dreams was to search for a wild fer de lance, a pit-viper that causes the most snake bite casualties in Central and South America. Known to scientists as Bothrops asper, the fer de lance has powerful venom which the snake uses to immobilize prey items. Unfortunately, the venom is also highly toxic to humans. In addition, its cryptic coloration and irascible personality make the fer de lance a formidable adversary.

My journey starts in Palo Verde, a biological field station on the west coast of Costa Rica. Situated in the middle of a dry forest, Palo Verde has unique fauna that have adapted to the weather conditions in the area.

Just touched down in Costa Rica. Geared up and ready for an adventure

Palo Verde, my first introduction to the Costa Rican dry forest, surpassed my wildest dreams; each morning, I would awake to the sound of howler monkeys announcing their presence to the entire jungle. Opening my door, I would see ctenosaurs (Ctenosaura similis), giant 4' long lizards, walking around, completely ignoring our presence.

A ctenosaur (Ctenosaura similis) walking around base camp

Another ctenosaur right outside my door (Courtesy of Rick Stanley)

A howler monkey (Alouatta spp.) leads his troupe across the canopy

The weather was hot and humid like you wouldn't believe. From the moment I woke up to the moment I closed my eyes to sleep, I was constantly sweating. The mosquitoes were also something else. Voracious little guys would completely coat your clothes, trying to get a taste of blood every moment of the day.

A mosquito net is a must when traveling in the tropics

Every morning, I would wake at sunrise and head out to search for reptiles. At 8 am, we would all congregate for breakfast, consisting of beans, rice, pineapple, fresh juice, and bacon. With the tropical sun already heating up, we would head out for a full morning of hiking and searching for reptiles.

On the river looking for American crocodiles

On the nose of the "croc boat"

An American crocodile (Crocodilus acutus)

For several days, I searched for a fer de lance to no avail. However, I did stumble upon many other exciting species:

A rear-fanged cat-eye snake (Leptodeira septentrionalis) we found during a night hike

Everything in the jungle seems to be bigger. This particular grasshopper was the smallest that I found


It might look like an overgrown mouse, but this small mammal is actually a marsupial (like a kangaroo)

Monkeys were everywhere at Palo Verde. From howler monkeys to capuchins (Cebus capucinus), these primates traveled in large troupes, jumping from tree to tree. While cute at a distance, these monkeys do not hesitate to bare their teeth and throw unsavory items (like their feces) at you. I learned a lesson to always watch out for them in the canopy after I felt a shower of sticks and feces on my back as I was looking for snakes in the underbrush and had accidentally wandered into the troupe's range.

Overlooking the floodplains of Palo Verde

A coati (Nasua spp.) is the south American relative of the raccoon

A giant water bug (those pincers are pretty intense)

A gecko (Eubelpharis spp.) we found during a night hike

A south American garter snake (Thamnophis spp.)

A cane toad (Bufo marinus). The large "warts" behind the toad's eye are parotid glands that produce a highly toxic poison that it uses to defend itself.

A giant smoky jungle frog (Leptodactylus pentadactylus)

The highlight of the Palo Verde leg of the expedition was finding a sunbeam snake (Xenopeltis spp.). These snakes are extremely rare during the wet season and virtually non-existent during the dry season. As we were in Palo Verde at the height of the dry season, this little guy was an amazing find. Sunbeam snakes have very docile personalities and forage for food on the forest floor. During the day, rays of light bounce off color pigments in the skin, causing a brilliant rainbow of iridescence. They literally shine like a beam of light at times, hence the name sunbeam. After taking the necessary measurements and photos for identification, we let the sunbeam snake free.