They tend to reach from 22-32 inches in length. Have a pair of heat-sensitive pits between the eyes and nostrils. This means that it does most of its hunting from late evening through early morning, and more than likely in, from, or around trees. When subduing its prey, the snake grabs it and holds on while it injects a hemotoxic venom. Eyelast vipers are usually not known to be an aggressive snake, however it strikes instantly if anyone brushes against it.
Vipers are also one of the most dangerous of the poisonous snakes on Central America.
Their venom affects the central nervous system of their victim as well as the cardiovascular system. With small animals the venom can kill within minutes, but larger animals rarely succumb unless the viper manages to inject a large amount of venom into the victim. Because the viper is arboreal, most bites to humans are to hands, fingers and occasionally to the face. They usually result in lots of pain, swelling, bleb formation, bruising and sometimes necrosis, that may lead to contraction or even amputation. The most common effects that happen from the venom are vomiting, diarrhea, prostration, or sometimes loss of conciousness.