Elizabeth Preston envisions how critters see the world:
Rattlesnakes have low-resolution color vision during the day and plenty of rod cells for a boost at night. But what sets rattlesnakes apart is their ability to sense infrared light. Similarly to vipers, pythons, and boas, the rattlesnake has special sensory tools called pit organs – a pair of holes on either side of the snout between the eye and the nostril. Suspended in each pit is a thin membrane that detects heat, says David Julius, a physiology professor at the University of California, San Francisco. Julius discovered that a neural receptor, TRPA1, present in the nerve cells connected to this membrane is responsible for snakes’ ability to transform infrared light into nerve signals. In humans, the same receptor triggers our pain response to certain spicy foods such as wasabi and mustard. But in snakes, it responds to the heat of nearby prey. The rattlesnake’s brain merges the information from the pit organs with information from the eyes so that a prey’s thermal image is overlaid on the visual one. Julius says it’s actually not hard for humans to approximate what the snake sees: Just look through an infrared camera.
The article also explores the vision of cats, birds, bees, and cuttlefish. Photo contrasting rattlesnake vision with human vision by Dr. Klaus Schmitt.
The Dish 