What is the only bat that feeds exclusively on blood?

The only mammals that feed exclusively on blood are vampire bats. All three living species—common, hairy-legged, and white-winged vampire bats—belong to the subfamily Desmodontinae and practice hematophagy.

Vampire bats live in Central and South America and hunt after dark. They locate sleeping animals, make a small incision with razor-sharp teeth, and lap up the blood rather than sucking it. Their saliva contains an anticoagulant called draculin, which helps keep the wound bleeding.

The common vampire bat usually feeds on mammals such as cattle and horses, while the hairy-legged and white-winged species mainly feed on birds. Despite their reputation, vampire bats do not drain their prey; a typical meal is modest, although it can add roughly 20–30% to the bat’s body weight.

Their specialized diet creates a serious risk: a bat may survive only about two days without food. To cope, vampire bats sometimes regurgitate blood for hungry colony members, an unusual example of food sharing among mammals.