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:
|LR/cd||Lower risk/conservation dependent||Species which were the focus of conservation programmes and may have moved into a higher risk category if that programme was discontinued.|
|LR/nt||Lower risk/near threatened||Species which are close to being classified as vulnerable but are not the subject of conservation programmes.|
|LR/lc||Lower risk/least concern||Species for which there are no identifiable risks.|
Sirenia is an order of fully aquatic, herbivorous mammals that inhabit rivers, estuaries, coastal marine waters, swamps, and marine wetlands. All four species are endangered.
The elephants comprise three living species and are the largest living land animals.
Rodents make up the largest order of mammals, with over 40 percent of mammalian species. They have two incisors in the upper and lower jaw which grow continually and must be keep short by gnawing. Most rodents are small though the capybara can weigh up to 45 kg (100 lb).
The lagomorphs comprise two families, Leporidae (hares and rabbits), and Ochotonidae (pikas). Though they can resemble rodents, and were classified as a superfamily in that order until the early 20th century, they have since been considered a separate order. They differ from rodents in a number of physical characteristics, such as having four incisors in the upper jaw rather than two.
The order Erinaceomorpha contains a single family, Erinaceidae, which comprise the hedgehogs and gymnures. The hedgehogs are easily recognised by their spines while gymnures look more like large rats.
The bats' most distinguishing feature is that their forelimbs are developed as wings, making them the only mammals in the world naturally capable of flight. Bat species account for about 20% of all mammals.
The order Philodota comprises the eight species of pangolin. Pangolins are anteaters and have the powerful claws, elongated snout and long tongue seen in the other unrelated anteater species.
The order Cetacea includes whales, dolphins and porpoises. 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.
Carnivorans include over 260 species, the majority of which eat meat as their primary dietary item. They have a characteristic skull shape and dentition.
The odd-toed ungulates are browsing and grazing mammals. They are usually large to very large, and have relatively simple stomachs and a large middle toe.
The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.