RATTLESNAKE: Rattlesnakes, like this western diamondback, have the uncanny ability to "see" in utter darkness. They can visualize heat, making them incredibly efficient at striking prey at night. Rattlesnakes belong to a New World family of snakes called Crotalidae, or pit vipers, which are named for a pair of pits located just behind the nostrils. Each of these pits is covered with a heat-sensitive membrane that can detect temperature changes as little as one-tenth of a degree. The pit organ transmits these signals to the same area of the brain that receives impulses from the optic nerve, which is connected to the eye. So, much like we can see visual light, the rattlesnake can also see heat. This allows it to ambush prey — mainly small, furry mammals, like mice, rats, ground squirrels and rabbits — from the cover of darkness. After injecting venom into its victim, the rattlesnake releases the struggling animal, then patiently tracks it by "tasting" the scent trail left behind. It does this by picking up odor particles with its forked tongue and passing them over a chemosensory organ in the roof of the mouth called the Jacobson's organ, which enhances the snake's sense of smell.