I had several encounters with them last year in YNP. one day on the Yellowstone there was not a Bison in sight. then within the hour about 30 of them decided to cross in the spot I was fishing. I tell ya no respect. I gave them some room. I figure a large animal with the brain the size of a baseball needs it's space.
a couple of days later on the Soda Butte I had a large herd just staying cool in the shade. they were on a bluff about 15 above me so it was interesting to watch and I figured if they start moving they would have to go 200 yards down river to cross.