a family of bats. Length, up to 7 cm. Desmodontidae feed exclusively on the blood of mammals and birds and even occasionally of humans (biting sleeping people). The bats alight noiselessly on their prey, painlessly break the skin with their sharp teeth to a depth of 4 mm, and lap up the seeping blood. They drink 20-40 milliliters of blood. The wounds continue to bleed for a long time; it is conjectured that the saliva of Desmodontidae contains an enzyme that prevents rapid coagulation of the blood.
They are distributed in South and Central America. There are three genera: Desmodus, Diaemus, and Diphylla, each with one species. The best-known is Desmodus rotundus. Desmodontidae are carriers of the rabies virus and of the causative agents of a number of other dangerous diseases of man and domestic animals. Desmodontidae are sometimes called vampire bats; however, bats of the genus Vampyrum do not feed on blood and belong to the family of leaf-nosed bats (Phyllostomidae).