Venomous Snakes

The term pit viper comes from the presence of paired, highly sensitive, thermoreceptor organs (pits) present on the forward portion of these snakes' heads. These structures, also known as foveal organs, serve the snake in locating prey, aiming strikes, and adjusting venom dose. The foveal organs can detect temperature changes of as little as 0.003 C (0.0054 F). A neurologic feedback loop between the foveal organs and the venom delivery apparatus may allow the snake to adjust the volume of venom it injects into a potential meal or a perceived threat.