The dietary diversity of bats is unmatched among living mammals. Most bats living in temperate areas, about 265 species, eat insects. Fruit bats, restricted to tropical areas, eat fruit and leaves, which they chew, swallowing the juice and spitting out the pulp. The long-tongued fruit bats (Macroglossus species) specialize in a diet of pollen and nectar, which they acquire using their elongated snout and unusually long tongue (up to one-third their body length). The fisherman bats (Noctilio species) of Central and South America catch small fish, while the frog-eating bat (Trachops cirrhosus) uses the calls of frogs to locate this prey, and can distinguish between the calls of poisonous and edible frogs. The large slit-faced bat (Nycteris grandis) of Africa eats small birds and even other bats, which are caught on the wing.
The infamous vampire bats (three genera in the subfamily Desmodontinae) dine on the blood of other mammals, such as domestic livestock, by making a shallow cut with their incisors and lapping the blood that flows from the wound; their saliva contains an anticoagulant that keeps the blood from clotting. These bats are quite agile on the ground, typically landing beside their sleeping victim, and crawling gingerly onto them to feed. Vampire bats are dietary specialists, but most other species consume several food items, varying their consumption to get enough protein and other nutrients.