vampire bat

The vampire bat is the only mammal to live as a parasite. It alights a few feet away from its victim and walks forwards on all fours. A small cut is made with its incisor teeth on a hairless part of the victim's body and the bat feeds on the oozing blood. Although the loss of blood is not severe, the bat may transmit serious diseases, such as rabies, to its victim.

South and Central American bat of the family Desmodontidae, of which there are three species. The common vampire Desmodus rotundus is found from northern Mexico to central Argentina; its head and body grow to 9 cm/3.5 in. Vampire bats feed on the blood of birds and mammals; they slice a piece of skin from a sleeping animal with their sharp incisor teeth and lap up the flowing blood. They chiefly approach their prey by flying low then crawling and leaping.

Vampire bats feed on all kinds of mammals including horses, cattle, and occasionally humans. The bite is painless and the loss of blood is small (about 1 cubic cm/0.06 cubic in); the victim seldom comes to any harm. Vampire bats are intelligent and among the few mammals to show altruistic behaviour (they adopt orphans and help other bats in need).

The other species are Diaemus youngi, the white-winged vampire, and Diphylla ecaudata, the hairy-legged vampire.