The bison, emblematic mammal of the American West

His chin beard and his bump on the back give it a unique look. Grazing for centuries in the vast American prairies, the favorite animal of Indians came close to extermination. Zoom on a species saved in extremis.

America’s heaviest mammal

The bison (Bison bison) is a ruminant mammal belonging to the order Artiodactyla and the family Bovidae. It measures between 2 and 3.5 m long and 1.50 to 2 m high at the withers. The animal understands two subspecies in America and a in Europe :

  • The bison of plains (Bison bison bison) is the smaller of the two American species: the male weighs an average of 739 kg and the female 440 kg. The mammal – which has been widely domesticated – frequents large and open environments (prairies, steppes) of the great American West;
  • The bison of wood (Bison bison athabascae) is the largest land mammal in North America. This species is mainly composed of animals living in freedom in the boreal forest (or taiga) of Canada and Alaska. It is less massive but heavier than that of the plains: the male weighs on average 880 kg and the female 540 kg;
  • BisonEurope (Bison bonasus) is found in Poland, Lithuania, Russia, Ukraine, Slovakia where it frequents deciduous forests, dense environments, glades, swamps. His hump is less prominent than that of his American cousins ​​and the average weight of the male is 800kg.

The bison, bearded and hunchbacked

The American bison is easily recognized by its typical silhouette: head and shoulders massive appear disproportionate to the slimming of his hindquarters. Its relatively short limbs have large rounded hooves and small dewclaws on the top of the hocks. The animal sports a broad, domed forehead enhanced by black horns and a long chin beard. The bison is distinguished above all by a bump imposing made up of muscles and fatty tissues and formed by the spiny structure of its vertebrae. Its coat combines long rough hairs as well as a down woolly that thickens in winter and lightens in summer. The head, shoulders and forelimbs have a sort of mane very brown curly while its rump is covered with a short and smooth hair of copper hue.

Bison are exclusively herbivorous

The bison feeds mainly ongrass and herbaceous plants: sedges, rushes and lichens. It appreciates grasses, small shrubs, young shoots, roots, bark, tree leaves as well as some fruits occasionally. The daily amount of vegetation consumed by the mammal can easily reach 25 kilos. After grazing, the ruminant lies down, regurgitates a bowl of food and chews it a second time. In winter, it digs the snow with its powerful muzzle to reach the grass.

The bison: particular signs

The bison devotes a large part of its day to thehygiene : To protect itself against insect bites and other parasites, it rolls up in muddy holes, in sand or dust, then rubs its head and sides against branches, rocks or tree trunks. His imposing size does not prevent him from running fast, up to 50 km / h and jumping 1.5 m in height if he feels threatened. He is also an excellent swimmer which keeps the head, the hump and the tail out of the water to cross a river and reach new pastures. His poor vision is compensated by hearing and smell sharp allowing it to detect an intrusion more than a kilometer away.

The intimidating herds of bison

While the wood bison live in small clans isolated, the plains bison form herds of thousands heads that represent an effective bulwark against his enemies. Its reproductive cycle can overwhelm its territory with a horde of newborns. The cohort of bovids deters predators from attacking and thus helps increase the rate of survival bisons. These animals gregarious constitute mixed and intergenerational groups whose top of the hierarchy is occupied by several males who constantly defend their position of leader during numerous fights, sometimes fatal, especially during the mating season.

The very protective bisonne

Bison reach their maturity sexual at the age of 4. During the breeding season – which runs from July to mid-September – dominant males fertilize several females. The bisonne gives birth at the end of a gestation a little over nine months old but before giving birth, she moves away from the herd in search of an isolated place. From birth, her cub weighs between 20 and 23 kg and has breast milk as the main food source until the onset of rumination, at the age of fifteen days. If the calf begins to graze the soft grass, the weaning only takes place very gradually to end around 9-12 months. Little by little, the protective mother ceases to intervene between her young and the members of the clan, allowing him to develop connections with its congeners.

The bison, almost wiped off the Earth

The predators Natural buffalo are the grizzly, gray wolf, puma and cougar. In the 1800s, North America was home to nearly 40 million wild bison which provided tribes native american meat and skin for shelter and clothing. Theextermination massive settlement undertaken by settlers decimated bovid populations to the point that in 1895, less than 1000 bison had survived. In 1907, the government created reservations and national parks and established laws prohibiting unauthorized shooting. Over the century, additional conservation measures have saved the species estimated at 500,000 individuals today. The International Union for the Conservation of Nature (IUCN) Red List of Threatened Species classifies the American bison as “near threatened”. The animal lives on average 18 to 22 years in the wild and 25 to 30 years in captivity.