Both animals are capable of running down a human, if they want to. I did some work a while back at Wichita Mountains National Wildlife Refuge, OK where fences are meer suggestions to the resident buffalo (bison). I was warned that buffalo raise their tails for two reasons, the second one being they are "extremely stressed" and if that happens, "very carefully and calmly get back in your vehicle". Um, thank you. Somewhere there was a photo of me examining fish, with free range buffalo looking on.
I guess it was a merciful thing that the Park Rangers found the injured buffalo and put it down - otherwise either the grizzlies or the wolves would have found it eventually.