Cows nurse their calves for at least 7 or 8 months, but most calves seem to be weaned before the end of their first year. At three years of age, bison cows are mature enough to produce a calf. Bison have a life expectancy around 15 years in the wild and up to 25 years in captivity. So, it’s great to know they’re still thriving!!! I would love to hear any comments you may have about this photo. I hope you have a great November.