It is fully mature at 3 years. Bison cows up to 30 years of age have been known to produce a calf. Single sex herd size is usually 4 - 20 animals. During the summer and early fall breeding season, herds of mixed sexes can be seen. Bison can run at speeds of near 30 mph and have been known to jump 6 foot fences.
Bison are most active in the cool early morning or late afternoon hours.
During the hottest periods, they can be seen laying, chewing their cuds and dust bathing. When Bison are agitated, they hold their tails upward in the shape of a question mark.