Molecular basis of infrared detection by snakes

Snakes are notoriously apt at generating 'thermal images' of predators or prey. The underlying physiology has been unclear, although in snakes such as pythons, vipers and boas, infrared signals are initially received by the pit organ. Here it is shown that pit-bearing snakes rely on heat detection by the ion channel TRPA1. This extends the sensory repertoire of the TRPA1 family of proteins, which detect chemical irritants in mammals and thermal variations in insects.