Common vampire bat

The common vampire bat (Desmodus rotundus) is a small leaf-nosed bat of Mexico, Central America and South America, and one of only three bat species that feed on blood. It averages about 9 centimeters in length, has silver-gray underparts and a flat, leaf-shaped nose, and carries razor-sharp incisors and canines, the upper incisors lacking enamel. It roosts in trees, caves, abandoned buildings, old wells and mines, and leaves at night to feed on the blood of mammals, mostly livestock such as cattle and horses, lapping it from a small cut with a grooved tongue while an anticoagulant in its saliva keeps the blood flowing. It is unusually social for a bat: females share regurgitated blood meals with roostmates, mostly close kin, and groom one another, while dominant males defend groups of females. Because it carries rabies and preys on livestock it is regarded as a pest, but the species is assessed as Least Concern, and its saliva inspired the clot-dissolving drug desmoteplase.