Yellowstone National Park is the only place in the United States where bison have lived continuously since prehistoric times. As of 2024, Yellowstone’s bison population is estimated to be around 5,400 individuals representing the nation’s largest bison population living on public land.
As the weather warms Yellowstone’s bison have begun to shed their thick winter coat in preparation for summer. The winter coat is incredibly dense and woolly providing much needed insulation to battle harsh winter conditions. As they shed their winter coat bison reveal shorter, darker summer coat underneath. This shedding process will continue through mid-summer with many bison still having patches of old, lighter-colored hair especially on their shoulders.
During shedding bison can be seen throughout the park wallowing in dirt and rubbing against any object that can support their weight to help remove the loose hair. This includes trees, bushes and in the case of this bison filmed this week at the Sepulcher Mountain Trailhead, one of Yellowstone’s the stoutly built trail signs.
If you happen upon wisps of crinkly hair stuck to trees, bushes, or trails signs inside Yellowstone, it may be from a bison trying to rid itself of its winter coat. As we head into the months of peak tourism in Yellowstone National Park, it is important to remember that the bison that roam the park have injured more people than any other animal and visitors are required to maintain at least 25 yards distance away from them at all times. Learn more about bison safety at Yellowstone National Park below:
Yellowstone National Park Bison Safety Guidelines:
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.
