An adult cow supplies the leadership. The olfactory sense of bison is excellent and is essential in detecting danger. Bison can hear very well as well. Bison are able to distinguish large objects from a distance of 1 km and moving objects 2 km away. Bison can communicate vocally through grunts and snorts.
Copulation is initiated by the bull and is quick.
During the rut, bulls fight among themselves. Now, however, because of their limited numbers, bison are found in many fewer habitats and their movements are very controlled. They formed the basis of the economy of a number of groups of Native Americans. The pre-Columbian population of bison in North America was estimated to be around 60 million. By 1890 the number was reduced to less than 1000.