This is a relatively small species that rarely exceeds 75 cm (2.5 feet) in length, with females being larger than males. They have a wide, triangular-shaped head, and eyes with vertical pupils. Like all pit vipers, they are solenoglyphous, having large, hypodermic needle-like fangs in the upper jaw that fold back when not in use, and have heat sensitive organs, or pits, located on either side of the head between the eye and nostril.
Its most distinguishing feature, and origin of its common name, is the set of modified scales over the eyes that look much like eyelashes. The eyelashes are thought to aid in camouflage, breaking up the snake's outline among the foliage where it hides. B. schlegelii occurs in a wide range of colors, including red, yellow, brown, green, even pink, as well as various combinations thereof. They often have black or brown speckling on the base color.
Common names: Eyelash viper, eyelash mountain viper, Schlegel's viper, Schlegel's palm viper, eyelash snake, horned palm viper. eyelash pit viper, Schlegel's pit viper. eyelash palm-pitviper. Also known as Bocaracá in Costa Rica and other Latin American countries.
