[1] The following tags are used to highlight each species' conservation status as assessed by the International Union for Conservation of Nature: Some species were assessed using an earlier set of criteria.
Species assessed using this system have the following instead of near threatened and least concern categories: The bats' most distinguishing feature is that their forelimbs are developed as wings, making them the only mammals capable of flight.
They are the mammals most fully adapted to aquatic life with a spindle-shaped nearly hairless body, protected by a thick layer of blubber, and forelimbs and tail modified to provide propulsion underwater.
There are over 260 species of carnivorans, the majority of which feed primarily on meat.
There are about 220 artiodactyl species, including many that are of great economic importance to humans.