Yellowstone National Park’s wildlife is one of the biggest features pulling tourists into the area. Bears, elk, wolves, coyotes, mountain goats, big horn sheep, moose, and of course bison can all make Yellowstone visits unique and unforgettable.
Unfortunately not all tourists that visit the national parks across the United States think as hard as they probably should, and the animals invite opportunities for people to be really stupid. The bison of Yellowstone in particular seem to attract lots of people who believe they can come close to or even pet the large beasts, leading to some dangerous and potentially deadly situations. Watching tourists behave in unintelligent ways as a nurse, knowing that you might have to help when stuff goes wrong, would probably not be a pleasant experience.
Yellowstone National Park requires at least 25 yards (75 feet) be given between humans and bison (most animals are 25 yards, bears and wolves are 100 yards). This is the space of about two school busses. The men that emergency nurse Heidi Irby captured in this video were certainly breaking that distance rule.
Yellowstone National Park on Bison Safety:
Bison have injured more people in Yellowstone than any other animal. Bison are unpredictable and can run three times faster than humans. Always stay at least 25 yards (23 m) away from bison.
- Give bison space when they are near a campsite, trail, boardwalk, parking lot, or in a developed area. If need be, turn around and go the other way to avoid interacting with a wild animal in close proximity. 
- Approaching bison threatens them, and they may respond by bluff charging, head bobbing, pawing, bellowing, or snorting. These are warning signs that you are too close and that a charge is imminent.
- Do not stand your ground. Immediately walk or run away from the animal. Spray bear spray as you are moving away if the animal follows you.