Once in Yellowstone, the first thing you bump into will almost certainly be a bison. Or bisons, a lot of bisons, as with the herd of more than 4.000 pieces they’re literarily everywhere. With the weight of 1.800 pounds and a pair of massive and pretty sharp horns, Yellowstone bisons don’t really have a natural enemy that is able to hunt them. Thus they look perfectly calm, and you most probably won’t run in any trouble with these creatures, unless it’s not your lucky day. The rule of thumb however is keeping a safe distance between you and the bisons, which is 25 yards (100 yards from bears and wolves).
More pics on my photoblog: http://www.skorobogatov.com/photoblog/ .