| These medium-sized vampire bats are most common in cattle country, finding large mammals (and very occasionally, humans) good sources of food. Vampire bats are the only mammals in the world whose only food is blood. A bat planning to feed on a cow lands close to it, crawls onto the animal, and uses a flap of skin on its nose like a heat-detector to find a good place to bite, a place where the blood flows close to the skin. Its teeth are sharp as razors; its bite is tiny and shallow. Its saliva contains an anticoagulant that keeps the cow’s blood flowing while the bat uses its tongue almost like a straw to drink its fill. As it feeds, the bat urinates. Blood is about half water, which the bat eliminates. Even so, after ingesting about two tablespoons of blood it is so full it can hardly fly. Back at the roost, if another bat has not succeeded in feeding that night, it will share its bounty by vomiting some blood for the other bat to eat.
Head and Body: 68-93 mm
Geoffroy Saint-Hilaire, É., 1810. Annales Muséum National D'Histoire Naturelle, Paris. 15:181.
Mammal Species of the World
Mammalian Species, American Society of Mammalogists' species account