Costa Rica: Arenal NP – Eyelash Viper

We spotted half a dozen of these little snakes – Eyelash Viper aka Eyelash Palm Pit-viper. They are real actively small in size – about 1/2 meter max – but quite poisonous and even deadly to humans. The venom is both hemotoxic and neurotoxic, containing procoagulants and hemorrhagic compounds that affect both the cardiovascular system and the central nervous system. The bite is delivered by retractable fangs, but generally these vipers are quite non-aggressive. They have modified scales above their eyes that look like eye lashes, hence the name. The Eyelash viper possesses heat sensitive organs, called pits, located on either side of the head, between the eyes and nostrils. These pit organs allow them to find potential prey by their body heat, a great evolutionary adaptation to a predator that hunts mainly at night. And last bu not least – they can change color – from silver to grey to green to red to brown – almost like chameleons. Amazing snakes!