Impact of bison grazing on the national park is so extensive it can be seen from space.
The encounter is just the latest example of Yellowstone visitors placing themselves and others in danger by getting too close to bison in the park.
Bison have injured more people in Yellowstone than any other animal, according to the National Park Service.
Today some 500,000 bison have been restored in over 6,000 locations.
Learning to interact with wildlife is not a part of the standard curriculum at most schools.
There are about 4,900 bison roaming the park.