Equidae

Equidae (sometimes known as the horse family) is the taxonomic family of horses and related animals, including the extant horses, donkeys, and zebras, and many other species known only from fossils. All extant species are in the genus Equus. Equidae belongs to the order Perissodactyla, which includes the extant tapirs and rhinoceros as well as several extinct families.

The term equid refers to any member of this family, including any equine.

Evolution

The oldest known fossils assigned to Equidae date from the early Eocene, 54 million years ago. They formerly were assigned to the genus Hyracotherium, but the type species of that genus now is regarded to be not a member of this family. The other species have been split off into different genera. These early Equidae were fox-sized animals with three toes on the hind feet, and four on the front feet. They were herbivorous browsers on relatively soft plants, and already adapted for running. The complexity of their brains suggest that they already were alert and intelligent animals. Later species reduced the number of toes, and developed teeth more suited for grinding up grasses and other tough plant food.

Equus

Equus may refer to:

Music

Transportation

See also

Burchell's zebra

Burchell's zebra (Equus quagga burchellii) is a southern subspecies of the plains zebra. It is named after the British explorer and naturalist William John Burchell. Common names include bontequagga, Burchell's zebra, Damara zebra, and Zululand zebra (Gray, 1824). Burchell's zebra is the only subspecies of zebra which may be legally farmed for human consumption in the UK.

Physical characteristics

Like most plains zebras, females and males are relatively the same size. Year-round reproduction observed in this subspecies in Etosha National Park, Namibia, concludes synchronization of a time budget between males and females, possibly explaining the lack of sexual dimorphism.

Damara zebras are described as being striped on the head, the neck, and the flanks, and sparsely down the upper segments of the limbs then fading to white. One or two shadow stripes rest between the bold, broad stripes on the haunch. This main, distinguishing characteristic sets the Zuzuland Zebra apart from the other subspecies. Gray (1824), observed a distinct dorsal line, the tail only bristly at the end, and the body distinctly white. The dorsal line is narrow and becomes gradually broader in the hinder part, distinctly margined with white on each side.

Kiang

The kiang (Equus kiang) is the largest of the wild asses. It is native to the Tibetan Plateau, where it inhabits montane and alpine grasslands. Its current range is restricted to Ladakh in Jammu and Kashmir, plains of the Tibetan plateau and northern Nepal along the Tibetan border. Other common names for this species include Tibetan wild ass, khyang and gorkhar.

Taxonomy

The kiang is closely related to the onager (Equus hemionus), and in some classifications it is considered a subspecies, E. hemionus kiang. Molecular studies, however, indicate that it is a distinct species. An even closer relative, however, may be the extinct Equus conversidens of Pleistocene America, to which it bears a number of striking similarities; however, such a relationship would require kiangs to have crossed Beringia during the Ice Age, for which little evidence exists. Kiangs can crossbreed with onagers, horses, donkeys, and Burchell's zebras in captivity, although, like mules, the resulting offspring are sterile. Kiangs have never been domesticated.