They may not be Dracula in disguise, but vampire bats (Desmodus rotundus) are still creepy nocturnal critters that need blood to survive. Scientists report in Nature that they have now figured out how these nightmarish mammals find the best spots to bite—and there’s a connection to humans and spicy foods.
When a vampire bat needs to feed, it quickly and silently gallops along the ground towards a victim, usually a sleeping goat, cow or bird. It then finds a vein and sinks its razor-sharp teeth through the flesh so delicately that its prey doesn’t awaken. As blood seeps out, the bat uses the grooves in its tongue to draw the liquid into its mouth using capillary action; the blood continues to flow because the bat’s saliva contains anti-coagulation chemicals.
Scientists had figured out years ago that the bats used pits on their noses to detect the heat given off by blood vessels. And now they’ve determined the details behind that detection. The bats have a modified form of a protein called TRPV1 that can be found on the ends of nerves in the pits of the bats’ noses.
In bats and other vertebrates, including humans, TRPV1 is the molecule responsible for detecting heat. It’s why you feel pain when you touch something hot or taste something with capsaicin. Vampire bats have the regular version of TRPV1 in their bodies but in their noses they produce a shortened form that activates at a lower temperature, perfect for finding a vein in the bats’ prey.