The early bison were enormous, weighing up to 5,000 pounds with horns that spanned more than 6 feet. Modern American bison bulls can be up to 5 to 6 feet tall at their shoulder and weigh more than 2,000 pounds. Cows tend to be smaller than the bulls, weighing around 800 to 1,200 pounds. The American bison can be characterized by its massive woolly head, broad forehead, short neck, and shoulder hump, which actually stores energy-rich fat. Both bulls and cows have true horns that are never shed. As for their hair, they have long dark hair that covers their head, neck, and shoulders, along with short, lighter hair that covers their hindquarters. All of this woolly hair actually makes their head appear larger than it is, not to mention their 8 to 10 inch beard. Their coat consists of long, coarse guard hairs and a thick woolly undercoat, along with a tuft of hair at the end of their tail. The American bison is born with reddish-brown fur, which changes to dark brown at around 2 to 3 months of age. They can live from twenty to forty years. They also have a four-chambered, ruminating stomach, and need around twenty to fifty pounds of food each day. In the winter, they use their massive heads to sweep away snow and access food. The American bison is primarily a grazer, but occasionally browses, and can actually live for several days without …show more content…
Their historic range covered most of central North America, but now only range freely in the Northwest Territories, northeast British Colombia, Wyoming, and Alaska. There are an estimated 15,000 to 20,000 that currently roam on public lands. However, private herds may contain up to 10 times the number on public lands. Large herds used to migrate up to 200 miles, and some wood bison still migrate over 100 miles. American bison form matriarchal groups. They use vocalizations that include grunts, snores, roars, bleats, and sneezes. They also use foot stamping and tooth grinding. Their visual communication is made up of a variety of head and body movements. They can also run up to 35 miles per hour for long periods of time. Due to their physical structure, American bison have a habit of facing into both storms and predators, rather than fleeing. They are also known to act indifferent towards wolves until an attack is initiated. They create wallows of dust and mud to roll in. This can serve either to relieve itches or cover their coat as a form of insect