Emerald tree boa photo courtesy of Jessie Cohen/NZP
Snakes
Pythons and boaconstrictors have pits along their lips that are actually infrared heat receptors that can tell the snake where their prey is. Pit vipers, rattlesnakes,and other poisonous snakes have these heat sensors also.Because the sensors don't involve vision, these snakes are able to strike their prey in total darkness.