Snake-mimic caterpillar of an undetermined species of Amazonian hawkmoth. The resemblance to the head and anterior portion of a venomous snake is amazing with even the horn-like head projections resembling a snakes forked tongue and the false eyespots appearing to glisten in the light. This, and several similar caterpillars from the region are often referred to as viper worms. Photographed off the Rio Orosa in the Peruvian Amazon.