Fewest teeth for a bat species

The bat species with fewest teeth is the common vampire bat (Desmodus rotundus), which has only 20 teeth in total. The upper incisors and upper canines, used for slicing through skin to inflict bleeding wounds, are large, but the other teeth are very tiny. This species is native to Mexico, Central America and much of South America.

All three species of true vampire bat have a very limited dentition due to their specialized blood-drinking diet rendering grinding teeth superfluous. The white-winged vampire bat Diaemus youngi normally has 22 teeth but occasionally lacks the pair of second upper molars, thus reducing the total count to 20; and the hairy-legged vampire bat Diphylla ecaudata has 26 teeth.

No known bats have the complete mammalian dentition of 44 teeth. The most teeth in bats is 38 – found in various genera within the families Natalidae, Thyropteridae, Myzopodidae, and Vespertilionidae, including the nearly worldwide genus Myotis.