Infrared Sensitivity in Snakes (C/N)

One of the best-known biological features of snakes is their ability to sense infrared thermal radiation, essentially allowing them to “see” radiant heat in their environment, including in other living creatures; even a blind snake is able to see infrared. Pit vipers, pythons, and some boas have infrared-sensitive receptors in deep grooves on the snout, which they use largely to hunt their prey, warm-blooded mammals. It was previously thought that these organs evolved primarily for prey detection, but recent evidence suggests that it was used for thermoregulation and predator detection–to allow the animal to find sources of heat without which its body could not function, and to avoid animals that would eat them, rather than to find animals that they could eat. This means that the infrared receptors are more general-purpose than previously thought.