Horse

:This article discusses ungulate mammals. For other meanings of horse, see Horse (disambiguation).

Natural History of the horse

In comparison to our understanding of the development of most animals, evolutionists have a good grasp on the evolution of the horse from the very early (around 55 million years ago) Hyracotherium or eohippus to the wild equids listed below. By natural selection, the toes of early horse ancestors reduced to the single central toe which forms the hoof of the modern equine. (Compare animals with 'cloven' hooves (2 toes), like cows, pigs and sheep.) Vestiges of other toes remain as the splint bones, the callus-like "chestnuts" on the inner sides of all four legs, and the "ergots" hidden in the hair of the underside of the fetlock joint. In his 1983 book Hen's Teeth and Horse's Toes (ISBN 0393311031), the evolutionary biologist Stephen Jay Gould cited rare instances of modern horses with true extra toes as evidence that minor genetic mutations can reintroduce ancestral features.

Related Topics:
Evolution of the horse - Natural selection - Ancestors - Stephen Jay Gould

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In nature, horses function as prey animals. They have a natural tendency to flee from danger, though they will fight if cornered. Their eyes lie to the side of the head, giving them a wide view while grazing (slightly less than 180 degrees to each side, overlapped in front and leaving a blind spot in the rear). Even domesticated horses startle easily and must, for the safety of riders, undergo careful introductions to strange objects and situations.

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Horses live in family groups in primarily grassland habitats. These normally consist of a mature stallion, his harem of about one to ten mares, and the mares' offspring. Once young males reach breeding age and begin to attempt to breed with mares or to challenge the herd stallion, the latter drives them out of the herd to form "bachelor bands" with other young stallions. Usually not until a stallion reaches 7 or 8 years old does he stand a real chance of acquiring mares, eventually becoming, if successful in the attempt, a "band stallion", i.e. having a harem of his own, having separated female equids from another stallion's band.

Related Topics:
Grassland - Harem

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An alpha mare dictates the direction in which a family herd travels, while the stallion brings up the rear, "herding" his family. Recently, researchers have observed that a form of democracy appears to exist among horses. For instance, if the majority of the herd wants to stop and eat, the whole herd follows suit.

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