Whale — According to modern terminology, whales are the larger members of the order Cetacea. This order of aquatic mammals is divided into three suborders: the Mysticeti, the baleen whales; the Odontoceti, the toothed whales; and the Archaeoceti, an extinct group known only through fossils. The toothed whales (Odontoceti) also include the smaller DOLPHIN and PORPOISE. The large baleen whales …

Weasel — Weasels are mammals in the genus Mustela of the Mustelidae family. Originally, the name “weasel” was applied to one species of the genus, the European form of the Least Weasel (Mustela nivalis). Early literary references to weasels, for example their common appearances in fables, refer to this species rather than to the genus as a whole, reflecting what …

Warthog — The Warthog (Phacochoerus africanus) (“African Lens-Pig”) is a wild member of the pig family that lives in Africa. The common name comes from the four large wart-like tusks found on the head of the warthog, which serve the purpose of defense when males fight. They are the only widely recognised species in their genus, though some authors divide …

Wapiti — The elk, or wapiti (Cervus canadensis), is the second largest species of deer in the world and one of the largest mammals in North America and eastern Asia. In the deer family (Cervidae), only the moose, Alces alces (called an “elk” in Europe), is larger. Wapiti are almost identical to red deer found in Europe, of which they …

Walrus — The walrus (Odobenus rosmarus) is a large flippered marine mammal with a discontinuous circumpolar distribution in the Arctic Ocean and sub-Arctic seas of the Northern Hemisphere. The walrus is the only living species in the Odobenidae family and is further subdivided into two or three subspecies; the Atlantic walrus (O. rosmarus rosmarus), the Pacific walrus (O. rosmarus divergens) …

Wallaby — A wallaby is any of about thirty species of macropod (Family Macropodidae). It is an informal designation generally used for any macropod that is smaller than a kangaroo or wallaroo that has not been given some other name. Very small forest-dwelling wallabies are known as pademelons (genus Thylogale) and dorcopsises (genera Dorcopsis and Dorcopsulus). The name wallaby comes …

Tree Shrew — The treeshrews (or tree shrews) are small mammals native to the tropical forests of Southeast Asia. They make up the families Tupaiidae and Ptilocercidae and the entire order Scandentia. There are 20 species in 5 genera. Treeshrews have the highest brain to body mass ratio of any animal, even higher than humans. Although called treeshrews, they are …

Tenrec — Tenrecidae (common name tenrecs) is a family of mammals found on Madagascar and parts of Africa. Tenrecs are widely diverse, resembling hedgehogs, shrews, opossums, mice and even otters, as a result of parallel evolution. They can occupy several environments including aquatic, arboreal, terrestrial and fossorial. Some of these species can be found in the Madagascar dry deciduous forests, …

Tasmanian Devil — The Tasmanian Devil (Sarcophilus harrisii), also referred to simply as ‘the devil’, is a carnivorous marsupial now found in the wild only in the Australian island state of Tasmania. The Tasmanian Devil is the only extant member of the genus Sarcophilus. The size of a small dog, but stocky and muscular, the Tasmanian Devil is now the …

Tayra — The Tayra (Eira barbara), also known as the Tolomuco or Perico ligero in Central America, is an omnivorous animal from the weasel family Mustelidae. It is the only species in the genus Eira. Tayras have an appearance similar to weasels and martens, growing to a size of about 60 cm, not including a 45 cm long tail. Most …