Here's reason enough to hunt with a cheque book.
http://www.cbc.ca/news/canada/north/yukon-bison-attack-todd-pilgrim-1.4398582
I live in the Yukon, I also hunt bison from time to time (although moose is my go to meat). My experience is once one goes down, the rest of the herd head for the horizon as soon as they see you. The guy wounded it and ended up in close proximity to a wounded animal....it attacked him....and then he milked the experience for all it was worth. He’s lucky to have walked away. 30-06 with 180 grain bullets works tickety boo. They taste amazing, but older bulls are tough. I’d say a cow moose is a more dangerous animal.