Terciopelo or well known as fer de lance (Bothrops asper). As far as the venom is concerned it is the third most dangerous land snake in the world. However, it kills the most people of all American snakes because of its inconspicuousness and lack of fear of humans. As most pit vipers it hunts at night in the vicinity of streams and dense vegetation. Under its eyes there are small pits, which are temperature receptors that are so sensitive it can detect change of temperature as little as 0.002'C The adder in the picture is a young specimen and I had a very narrow escape when I almost stepped on. It was another important lesson in the way how to move in the jungle at night time.