The Snake of Many Colors

Eyelash Pit-viper photographed in Drake Bay, Costa Rica

One of the most beautiful and impressive snakes in Costa Rica is the Eyelash Pit-viper, Bothriechis schlegelii. They have countless color variations, and many morphs have been documented and can be observed even in the same litter! An example of these amazing variations can be seen by following this link: http://blog.inbio.ac.cr/inbio/?p=690 to Alejandro Solórzano’s post in INBio’s blog. Like most other Costa Rican Pit-vipers, Eyelash Pit-vipers give live birth. The two births pictured on his blog were documented by Mr. Solórzano at the National Serpentarium. In Drake Bay all of the Eyelash Pit-vipers we have encountered have had some variation of the mottled, green morph shown on the photograph above. Curiously, in Corcovado National Park, at Sirena Station, the only individuals we have found have had the yellowish, mottled morph featured below.

Eyelash Pit-viper photographed in Corcovado National Park, Sirena Station

These small, arboreal snakes are found throughout Costa Rica’s lowland rainforests. Their common name is derived from the specialized scales located above their eyes. These curiously shaped scales curve upward, resembling eyelashes. The scales’ function is still unknown, although some scientists theorize the scales may provide eye protection to the snakes as they make their way through the thick, often tangled arboreal vegetation which they inhabit.

Eyelash Pit-vipers have a small, prehensile tail which also greatly enhances their arboreal

Eyelash Pit-viper photographed in Drake Bay, Costa Rica

lifestyle. These sedate snakes are sit-and-wait predators and may spend several days on a perch waiting for their prey to blunder by. When this happens, the lethargic viper springs into action with blinding speed and delivers its deadly bite.

Once they have their prey, Eyelash Pit-vipers will hold on to it until it has succumbed to their venom. The venom not only kills its prey, but immediately begins digesting it, even before it is eaten. This allows Pit-vipers to take larger prey than non-venomous snakes. Prey items may include: lizards, frogs, bats and birds. Some scientists think that Eyelash Pit-vipers, especially the golden morph, may intentionally perch on flowers with the intention of ambushing unsuspecting hummingbirds as they come in to feed. Hummingbirds are very attracted to red and yellow….in this case a fatal attraction.

In Drake Bay we don’t tend to see these amazing creatures as often as we do other snakes. By far, our most common Pit-viper here is the Fer-de-lance, Bothrops asper. The last two nights we have been fortunate enough to have encountered a large (approximately 50 cm long) and incredibly beautiful Eyelash Pit-viper during the Night Tour. The snake’s photograph is included at the top of this post.

Eyelash Pit-viper photographed in Drake Bay, Costa Rica

Posted by Gianfranco

The Bluntheaded Snake: the ultimate lizard predator

One of the most strikingly specialized reptiles making its home in Drake Bay’s rainforest is

Bluntheaded Snake – Imantodes cenchoa

the Common Bluntheaded Snake, Imantodes cenchoa. These common nocturnal snakes are unlikely to be confused with any other snake in the area besides their close relatives: the rarely seen Banded Bluntheaded Snake (Imantodes gemnistratus) and the equally rare Speckled Bluntheaded Snake (Imantodes inornatus). Their slender, streamlined body sets these snakes apart from most other snakes and is crucial in capturing their favorite meals: sleeping lizards.

Bluntheaded SnakeIn Costa Rica, most lizards are diurnal and usually sleep through the night. Due to the countless threats faced by these creatures once darkness shrouds the forest, lizards have developed an ingenious survival strategy.

When choosing a perch to pass the night, most lizards wisely seek out the mid-line of a leaf or a very delicate branch or vine. This way, if they feel the movement of something moving up the plant to eat them sometime during the night, they can simply drop to the ground and make a quick escape from danger. Generally, this is a really good strategy, but the Bluntheaded Snake’s highly specialized skeletal structure helps them surpass it.

The Bluntheaded Snake’s skeletal structure is not unlike the structure of an I-beam. In cross section, the snake’s body is more reminiscent of a triangle than the more common tubular shape of most other snakes. This, along with interlocking vertebrae and reinforcing back scales, allows Bluntheaded Snakes to stretch more than half of their body into mid-air and snatch the unsuspecting lizards from their perch without ever touching the plant. A very long, prehensile, tail has the strength to support all of the Bluntheaded Snake’s body weight, giving them an extra advantage when hunting from above. Also, the snake has massive

Bluntheaded Snake feeding on an Anole Lizard

eyes which it can actually cast downward, providing Bluntheaded Snakes an effortless, inconspicuous view from above. All things considered, the poor lizards have little chance against such a formidable predator. The moral of the story: in the rainforest every good strategy has an even better counter-strategy.

Bluntheaded Snakes are rear-fanged snakes which are used to inject a mild venom. Once

they have secured their prey, their venom will immobilize it before they begin feeding. They can take prey up to ten times the size of their very narrow neck and adult snakes can easily feed on juvenile Green Iguanas and Basilisks. Despite being mildly venomous, Bluntheaded Snakes are docile and gentle creatures.

They do not bite as a defensive reaction and are easily handled. An encounter with a Bluntheaded Snake is always very special indeed. It gives our guests on the Night Tour the chance to handle these magnificent creatures, dispelling the ingrained fear of snakes held by many and replacing it with admiration and respect for a creature that has evolved to dominate its niche.

Posted by Gianfranco