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Bat Facts
Bats are mammals. Though sometimes called "flying rodents", "flying mice," or even mistaken for bugs and birds, bats are neither mice nor rodents, and certainly not arthropods. There are two suborders of bats:
Megachiroptera (megabats)
Microchiroptera (microbats/echolocating bats)
Despite the name, not all megabats are larger than microbats. The major distinction between the two suborders is based on other factors:
Microbats use echolocation, whereas megabats do not (except for Rousettus and relatives, which do).
Microbats lack the claw at the second toe of the forelimb.
The ears of microbats don't form a closed ring, but the edges are separated from each other at the base of the ear.
Microbats lack underfur; they have only guard hairs or are naked.
Townsends's Big-eared Bat, Corynorhinus townsendiiMegabats eat fruit, nectar or pollen while microbats eat insects, blood (small quantities of blood of animals), small mammals, and fish, relying on echolocation for navigation and finding prey.
Genetic evidence, however, indicates that some microbats ("Yinochiroptera") are more closely related to megabats than to the other microbats ("Yangochiroptera"). There is some morphological evidence that Megachiroptera evolved flight separately from Microchiroptera; if so, the Microchiroptera would have uncertain affinities. When adaptations to flight are discounted in a cladistic analysis, the Megachiroptera are allied to the primates by anatomical features that are not shared with Microchiroptera.
Little is known about the evolution of bats, since their small, delicate skeletons do not fossilize well. However a late Cretaceous tooth from South America resembles that of an early Microchiropteran bat. The oldest known definite bat fossils, such as Icaronycteris, Archaeonycteris, Palaeochiropteryx and Hassianycteris, are from the early Eocene (about 50 million years ago), but they were already very similar to modern microbats. Archaeopteropus, formerly classified as the earliest known megachiropteran, is now classified as a microchiropteran.
Bats are traditionally grouped with the tree shrews (Scandentia), colugos (Dermoptera), and the primates in superorder Archonta because of the similarities between Megachiroptera and these mammals. However, molecular studies have placed them as sister group to Ferungulata, a large grouping including carnivorans, pangolins, odd-toed ungulates, even-toed ungulates, and whales.
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