The common vampire bat (Desmodus rotundus) is a small, leaf-nosed bat native to the Americas. It is one of three extant species of vampire bat, the other two being the hairy-legged and the white-winged vampire bats. These species are the only known parasitic mammals. The common vampire bat mainly feeds on the blood of livestock, approaching its prey at night while they are sleeping. It uses its razor-sharp teeth to cut open the skin of its hosts and laps up their blood with its long tongue.