Eyelash Viper (Bocaracá)

Overview

The eyelash viper (Bothriechis schlegelii) is a small, stout arboreal pit viper with one of the most recognizable silhouettes in the rainforest: a coiled rope of scales on a palm frond, distinguished by the enlarged superciliary scales above each eye — the “eyelashes” — and an extraordinarily variable color palette. Color morphs across the species’ range include bright yellow (oropel in Costa Rican Spanish), olive green, brown-mottled, and pink. Adults measure 55–82 cm.

The pit organs between eye and nostril detect infrared radiation, allowing the snake to locate warm-blooded prey in complete darkness. The diet includes small rodents, frogs, hummingbirds, and lizards. Hunting strategy is pure ambush: coil on a branch, wait, strike, and wait again for the prey to die before following its scent trail to the body.

Venom contains phospholipase A2 enzymes and metalloproteases that cause local pain, edema, and tissue damage. Bites are medically significant and require prompt treatment; however, bites on tourists are extremely rare, as the snake does not pursue and typically strikes only when touched.

Why Tortuguero

Tortuguero’s humid lowland forest and secondary growth provide the humid, closed-canopy habitat this species depends on. The park is one of the few places in Costa Rica where the species has been specifically documented by name in wildlife inventories and naturalist reports. The dense canal-side vegetation — heliconias, palms, and low-hanging branches — provides ideal ambush perches.

The bocaracá is arguably the most visually striking snake a visitor to Tortuguero is likely to encounter, given that the bright yellow oropel morph is occasional on vegetation within clear view of boat tours. That said, the majority of individuals are cryptic and go completely unseen even by experienced guides.

How to see one (honestly)

• Scan low branches and palm fronds carefully during slow boat tours. Look for an unnaturally uniform coil of color — the oropel morph is unmistakably bright yellow, often draped on a heliconia or similar broad-leaved plant.
• Night walks on the Tortuguero trail system (with a licensed guide) are the most reliable way to find the cryptic green and brown morphs.
• Never touch or prod any snake you find. Even an apparently sleeping coil can strike with exceptional speed.
• A sighting is memorable but far from guaranteed; guides who run the canals for years may see only a handful per season.

Status note

The IUCN assessed Bothriechis schlegelii (in the broad sense) as Least Concern in 2017, citing adaptability to secondary forest and agricultural habitats including banana and coffee plantations. The principal long-term threats are deforestation and, within its range, collection for the illegal pet trade. A 2024 systematic revision split the species complex into multiple distinct species; the taxonomy of Central American populations including Tortuguero is under active scientific review. Names and range boundaries may be revised in forthcoming publications.