Pythons, boas and pit vipers (the family that includes rattlesnakes) see the world pretty much as we do, but with a twist: they can “see” in infrared too. This allows them to track their prey by their body heat from up to a metre away. They do this using relatively simple organs, called pits, which lie near their nostrils. These differ slightly among different snakes but are always a small dip containing a membrane that is packed with heat-sensitive nerve endings which act as infrared receptors.
