Do Bison Bulls and Cows Mate for Life?

When Bison breed, does the bull & female mate for the duration of the pregnancy?  For life or does the bull service many cows?

Answer:

In reply to your questions bison do not mate for life.  A bull will generally start courting a female just before she goes into estrus and may stay with her for a day or two after having bred her.  The time (generally only a matter of days) that a bull spends with a cow varies quite a bit between bulls but they do not stay with the cow for the entire pregnancy. 

You are correct that a bison bull will service many cows during the breeding season, much like the beef bull.  In a population of bison you may find that one bull has serviced a majority of the cows in the duration of the breeding season.  However, courting behaviour and the length of courting can be longer in bison than in cattle. 

On rare occasions you may find a bison bull that has "fallen in love" and will not leave the company of a particular cow or spends a long time with one cow before seeking out another one that is coming into estrus.  This is rare but has been observed. 

There are many published reports on reproductive behaviour in bison and if you think you might be interested please feel free to contact the Alberta Bison Centre .  The Bison Centre also has a Bison Centre Resource Library that carries a wide range of information on bison.  

I hope this information helps in answering your questions. .

Larissa Helbig
Diversified Livestock Production Specialist
Alberta  Agriculture, Food and Rural Development
(780)986-4100