A bison has a shaggy, dark brown winter coat, and a lighter weight, lighter brown summer coat. Bison can reach up to 2m (6.6 ft) tall, 3m (10 ft) long, and weigh 400-1000 kg (900-2,200 pounds). The biggest specimens on record have weighed as much as 1,130kg (2,500 pounds). The heads and forequarters are massive, and both sexes have short, curved horns, which they use in fighting for status within the herd and for defence. Bison were the most numerous single species of large wild mammal on Earth. Some references state that the Bison is the largest living terrestrial mammal on the planet. Bison have been hunted for centuries for their meat and skins. They are now also farmed for these products around the world including Australia. Bison have few natural predators due to their massive size, allowing them to defend themselves very well.
Herds will normally increase in August which is the breeding season. One dominant male will mate most of the females in the herd. Younger, sexually mature males may exist in the herd with little or no mating impression over the herd. The gestation period for females is 270-300 days with 1 calf being born, twins are extremely rare. Weaning occurs at 6 months. Bison become sexually mature at 2-3 years and have a lifespan of up to 25 years.
Bison roam in herds grazing in open plains. The large size of individuals and herds has given them protection from many predators. Observations tend to show bison are more active grazing during the day time, particularly at dawn and dusk. This may be to avoid the heat in the middle of the day. These animals do graze well in very cold conditions with heavy snow cover and will paw down through snow with their hooves to feed on buried plants and shrubs.
These animals are herbivores grazing on large open plains. Their diet consists of a variety of grasses and associated plants.
Due to the bison being hunted almost to extinction and their numbers being replenished and protected through managed breeding programs, the distribution has greatly been reduced to smaller herds in reserves and parks. These animals are still bred domesticaly and are not threatened. The distribution map does indicate their original range and not the current one which is greatly reduced.