Bison are large bovines in the genus Bison within the tribe Bovini. Two extant and numerous extinct species are recognised.
Of the two surviving species, the American bison, B. bison, found only in North America, is the more numerous. Although colloquially referred to as a buffalo in the United States and Canada, it is only distantly related to the true buffalo. The North American species is composed of two subspecies, the Plains bison, B. b. bison, and the wood bison, B. b. athabascae, which is the namesake of Wood Buffalo National Park in Canada. A third subspecies, the eastern bison (B. b. pennsylvanicus) is no longer considered a valid taxon, being a junior synonym of B. b. bison. References to "woods bison" or "wood bison" from the eastern United States refer to this subspecies, not B. b. athabascae, which was not found in the region. The European bison, B. bonasus, or wisent, or zubr, or colloquially European buffalo, is found in Europe and the Caucasus, reintroduced after being extinct in the wild.
The American bison and the European bison (wisent) are the largest surviving terrestrial animals in North America and Europe. They are typical artiodactyl (cloven hooved) ungulates, and are similar in appearance to other bovines such as cattle and true buffalo. They are broad and muscular with shaggy coats of long hair. Adults grow up to 2 metres (6 feet 7 inches) in height and 3.5 m (11 ft 6 in) in length for American bison and up to 2.1 m (6 ft 11 in) in height[6] and 2.9 m (9 ft 6 in) in length for European bison. American bison can weigh from around 400 to 1,270 kilograms (880 to 2,800 pounds) and European bison can weigh from 800 to 1,000 kg (1,800 to 2,200 lb). European bison tend to be taller than American bison.
Bison are nomadic grazers and travel in herds. The bulls leave the herds of females at two or three years of age, and join a herd of males, which are generally smaller than female herds. Mature bulls rarely travel alone. Towards the end of the summer, for the reproductive season, the sexes necessarily commingle.
American bison are known for living in the Great Plains, but formerly had a much larger range, including much of the eastern United States and parts of Mexico. Both species were hunted close to extinction during the 19th and 20th centuries, but have since rebounded. The wisent in part owes its survival to the Chernobyl disaster, as the Chernobyl Exclusion Zone has become a kind of wildlife preserve for wisent and other rare megafauna such as the Przewalski's horse, though poaching has become a threat in recent years. The American Plains bison is no longer listed as endangered, but this does not mean the species is secure. Genetically pure B. b. bison currently number only about 20,000, separated into fragmented herds—all of which require active conservation measures. The wood bison is on the endangered species list in Canada and is listed as threatened in the United States, though numerous attempts have been made by beefalo ranchers to have it entirely removed from the Endangered Species List.
The bovine tribe (Bovini) split about 5 to 10 million years ago into the buffalos (Bubalus and Syncerus) and a group leading to bison and taurine cattle. Genetic evidence from nuclear DNA indicates that the closest living relatives of bison are yaks, with bison being nested within the genus Bos, rendering Bos without including bison paraphyletic. The mitochondrial DNA of European bison is more closely related to that of domestic cattle and aurochs, which is either suggested to be the result of incomplete lineage sorting or ancient introgression. Bison are widely believed to have evolved from a lineage belonging to the extinct genus Leptobos during the Late Pliocene to Early Pleistocene in Asia. The earliest members of the bison lineage, known from the Late Pliocene to Early Pleistocene of the Indian Subcontinent (Bison sivalensis) and China (Bison palaeosinensis), approximately 3.4-2.6 million years ago (Ma) are placed in the subgenus Bison (Eobison). The oldest remains of Eobison in Europe are those Bison georgicus found in Dmanisi, Georgia, dated to around 1.76 Ma. More derived members of the genus are placed in the subgenus Bison (Bison), which first appeared towards the end of the Early Pleistocene, around 1.2 Ma, with early members of the subgenus including the widespread Bison schoetensacki. The steppe bison (Bison priscus) first appeared during the mid-Middle Pleistocene in eastern Eurasia, and subsequently became widely distributed across Eurasia. During the late Middle Pleistocene, around 195,000-135,000 years ago, the steppe bison migrated across the Bering land bridge into North America, becoming ancestral to modern American bison, as well as extinct forms such as the largest known bison, the long-horned Bison latifrons, and the smaller Bison antiquus, which became extinct at the end of the Late Pleistocene. Modern American bison are thought to have evolved from B. antiquus during the Late Pleistocene-Holocene transition via the intermediate form Bison occidentalis. The European bison, Bison bonasus, first appeared in Europe during the late Middle Pleistocene, where it existed in sympatry with the steppe bison. Its relationship with other extinct bison species is unclear, though it appears to be only distantly related to the steppe and American bisons, with possibly some interbreeding between the two lineages during the Middle Pleistocene. The steppe bison survived into the early-mid Holocene in Alaska-Yukon and eastern Siberia, before becoming extinct.
The Amur leopard can easily be differentiated from other leopard subspecies by its thick, pale cream-colored fur, particularly in winter. Rosettes on the flanks are 5 cm × 5 cm (2.0 in × 2.0 in) and widely spaced, up to 2.5 cm (0.98 in), with thick, unbroken rings and darkened centers. Its fur is fairly soft with long and dense hair. The length of hair on the back is 20–25 mm (0.79–0.98 in) in summer and up to 70 mm (2.8 in) in winter. The winter coat varies from fairly light yellow to dense yellowish-red with a golden tinge, or rusty-reddish-yellow. In summer, the fur is brighter, with more vivid coloration pattern. It is rather small in body size, with males larger than females. Males measure 107–136 cm (42–54 in) with a 82–90 cm (32–35 in) long tail, a shoulder height of 64–78 cm (25–31 in), and a weight of 32.2–48 kg (71–106 lb). Females weigh 25–42.5 kg (55–94 lb).
The North Chinese leopard was first described on the basis of a single tanned skin which was fulvous above, and pale beneath, with large, roundish, oblong black spots on the back and limbs, and small black spots on the head. The spots on the back, shoulders and sides formed a ring around a central fulvous spot. The black spots on the nape were elongated, and large ones on the chest formed a necklace. The tail was spotted and had four black rings at the tip.
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. In the process of wallowing, bison may become infected by the fatal disease anthrax, which may occur naturally in the soil.
Bison 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 up to 56 km/h (35 mph) and cover long distances at a lumbering gallop.
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 what is a typical weight of 900 to 1,200 kilograms (2,000 to 2,700 lb) moving at 50 km/h (30 mph). The hind legs can also be used to kill or maim with devastating effect. In the words of early naturalists, they were dangerous, savage animals that feared no other animal and in prime condition could best any foe (except for wolves and brown bears).
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.
