kg (B.b.athabascae) in males, and 360 to 640 kg with medians of 450 to 497.6 kg in females, although the lowest weights probably representing typical weight around the age of sexual maturity at 2 to 3 years of age.

The heaviest wild bull for B.b.bison ever recorded weighed 1270 kg while there had been bulls estimated to be 3000 lb. B.b.athabascae is significantly larger and heavier on average than B.b.bison while the number of recorded samples for the former was limited after the rediscovery of a relatively pure herd. Elk Island National Park,