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Bison
American bison/American buffalo (Bison bison)
European bison/wisent (Bison bonasus)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Infraclass:	Eutheria
Order:	Artiodactyla
Family:	Bovidae
Subfamily:	Bovinae
Genus:	'bison' Hamilton Smith, 1827
Species
†B. antiquus B. bison B. bonasus †B. latifrons †B. occidentalis †B. priscus

Members of the genus Bison are large, even-toed ungulates within the subfamily Bovinae. Two extant and four extinct species are recognized. The surviving species are the American bison, also known as the American buffalo (although it is only distantly related to the true buffalo), Bison bison (with two subspecies, the plains bison, Bison bison bison, and the wood bison, Bison bison athabascae), found in North America, and the European bison, or wisent (Bison bonasus), found in Europe and the Caucasus. While these species are usually grouped into their own genus, they are sometimes included in the closely related genus Bos,^[1] together with cattle, gaur, kouprey and yaks, with which bison have a limited ability to interbreed.

Description[link]

Magdalenian bison on plaque, 17,000–9,000 BCE, Bédeilhac grottoe, Ariège.

The American bison and the European wisent are the largest terrestrial animals in North America and Europe. Bison are good swimmers and can cross rivers over half a mile (1 km) wide. Bison are nomadic grazers and travel in herds. The bulls leave the herds of females at 2 or 3 years of age, and join a male herd which is generally smaller than the female herds. Mature bulls rarely travel alone. Both sexes get together for the reproductive season, towards the end of the summer.^[2] American bison are known for living in the Great Plains. Both species were hunted close to extinction during the 19th and 20th centuries, but have since rebounded. The American plains bison is no longer listed as endangered, but the wood bison is on the endangered species list in Canada.^[3]

Although superficially similar, there are a number of physical and behavioural differences between the American and European bison. The American species has 15 ribs, while the European bison has 14. The American bison has four lumbar vertebrae, while the European has five.^[4] Adult American bison are not as rangy in build, and have shorter legs.^[5] American bison tend to graze more, and browse less than their European cousins. Their anatomies reflect this behavioural difference; the American bison's head hangs closer to the earth than the European's. The body of the American bison is typically hairier, though its tail has less hair than that of the European bison. The horns of the European bison point through the plane of their faces, making them more adept at fighting through the interlocking of horns in the same manner as domestic cattle, unlike the American bison, which favours butting.^[6] American bison are more easily tamed than their European cousins, and breed with domestic cattle more readily.^[7]

Genetic history[link]

A 2003 study of mitochondrial DNA indicated four distinct maternal lineages in tribe Bovini:

1. taurine cattle and zebu,
2. wisent,
3. American bison and yak, and
4. banteng, gaur, and gayal.

However, Y chromosome analysis associated wisent and American bison.^[8] An earlier study using amplified fragment length polymorphism (AFLP) fingerprinting showed a close association of wisent and American bison and probably with yak, but noted that the interbreeding of Bovini species made determining relationships problematic.^[9]

During the population bottleneck, American bison were interbred with domestic cattle. Accidental crossings were also known to occur. Generally, male domestic bulls were crossed with buffalo cows, producing offspring of which only the females were fertile. Genetic analysis has found a high degree of intermixture in modern commercial bison herds. Some cattle breeds are intentionally bred with bison to produce, for instance, Beefalo hybrids. Wisent-American bison hybrids were briefly experimented with in Germany (and found to be fully fertile) and a herd of such animals is maintained in Russia all the time. A herd of cattle-wisent crossbreeds (Zubron) is maintained in Poland. First-generation crosses do not occur naturally, requiring caesarean delivery. First-generation males are infertile.

Behavior[link]

Wallowing is a common behavior of bison. A bison wallow is a shallow depression in the soil, either wet or dry. Bison roll in these depressions, covering themselves with mud or dust. Possible explanations suggested for wallowing behavior include grooming behavior associated with moulting, male-male interaction (typically rutting behavior), social behavior for group cohesion, play behavior, relief from skin irritation due to biting insects, reduction of ectoparasite load (ticks and lice), and thermoregulation.^[10] In the process of wallowing, bison may become infected by the fatal disease anthrax, which may occur naturally in the soil.^[11]

A group of images by Eadweard Muybridge, set to motion to illustrate the movement of the bison

The bison's temperament is often unpredictable. They usually appear peaceful, unconcerned, even lazy, yet they may attack anything, often without warning or apparent reason. They can move at speeds of up to 35 mph (56 km/h) and cover long distances at a lumbering gallop.^[12]

Their most obvious weapons are the horns borne by both males and females, but their massive heads can be used as battering rams, effectively using the momentum produced by 2,000 pounds (900 kg) moving at 30 mph (50 km/h). The hind legs can also be used to kill or maim with devastating effect. At the time bison ran wild, they were rated second only to the Alaska brown bear as a potential killer, more dangerous than the grizzly bear. In the words of early naturalists, they were a dangerous, savage animal that feared no other animal and in prime condition could best any foe.^[12]

The rutting, or mating, season lasts from June through September, with peak activity in July and August. At this time, the older bulls rejoin the herd, and fights often take place between bulls. The herd exhibits much restlessness during breeding season. The animals are belligerent, unpredictable and most dangerous.^[12]

Diet[link]

This section requires expansion.

Bison have a fairly simple diet. The bison's main food is grass. Bison also eat the low-lying shrubbery that is available. In the winter, bison forage in the snow looking for grass. If there is little grass available, bison have to resort to eating the twigs of shrubs.^{[citation needed]}

Predators[link]

This section requires expansion.

Due to their large size, few predators attack bison. However, wolf packs can take down a bison. There are even documented cases of a single wolf taking down bison (Carbyn et al., 1993). Brown bears will also prey on calves, and commonly drive off wolves to take over their kills.^[2]

Illness[link]

This section requires expansion.

The main cause of illness in bison is malignant catarrhal fever (MCF).^[13]

See also[link]

• African buffalo
• American bison (Bison bison)
• Bison antiquus
• Bison latifrons (Giant bison)
• Gaur
• Wood bison
• Bison hunting
• Great bison belt
• Wisent (European bison, Bison bonasus)
• Yellowstone Park Bison Herd
• Antelope Island Bison Herd
• Antelope Island
• Antelope Island State Park
• Wind Cave Bison Herd
• Henry Mountains Bison Herd
• Henry Mountains
• Book Cliffs

References[link]

External links[link]

Wikimedia Commons has media related to: Bison

Wikisource has the text of the 1911 Encyclopædia Britannica article Bison.

• History of Bison Blend Cattle