The American bison (also known as a buffalo) is a very large animal once common on the grasslands of North America. It was nearly made extinct in the 19th century by reckless shooting, but has now being re-established in herds across the continent.

The word bison comes from the Greek for 'ox-like' animal. It has a heavy body, with massive front quarters and a shaggy coat. It can weigh up to a ton. Both sexes have short, curved horns.

They are grazing animals that continually move about as herds. Bison graze on land that is bitterly cold and covered with snow in winter. They use their heads to push the snow out of the way so they can get to the grasses below.

The video below shows a 'maternal herd', consisting only of females and young males. Young male bison leave the herd when they grow up, and only return to the female herd in the mating season.

A large adult bison can fend off most attacks by wolves, and it is the young and elderly which are most at risk. Bison live for about 15 years.