Bison head-butts car stuck in traffic jam in Yellowstone National Park

A bison in Yellowstone National Park was seen aggressively ramming its head into a vehicle on August 17. 

The car was one in a line of dozens stuck in a traffic jam waiting for a large herd of bison to clear the road. Officials with the park said now is the height of the animals’ mating season, so they’re slowly migrating to the Lamar and Hayden valleys. 

The bison mating season, known as rut, lasts each year from June to September, with most activity occurring between July and August. Male bison, or bulls, fight with each other to prove they are strong mates to the females of the herd, according to the park

Visitor William Ogonowski was capturing video of the herd crossing when two bison began to get aggressive. 

The video shows the animals bellowing and grunting as they move around cars stopped in the traffic jam. 

"Oh no, they’re fighting right in front of those people!" Ogonowski says.

Then, just as Ogonowski notes how close the bison are to the cars, a bison suddenly head-butts the car directly in front.

Bison are unpredictable, have injured more people in Yellowstone than any other animal and can run three times faster than humans, park officials said. The park requires people to stay more than 25 yards away from all large animals, including bison and moose, and at least 100 yards away from bears and wolves.

At least two gorings this year have been reported involving bison at the park. 

In June, a Colorado man holding a child was tossed by a charging bison while he was holding a child. Both were OK. 

And in May, a 25-year-old Ohio woman got within 10 feet of a bison before it gored and tossed her, causing a puncture wound and other injuries. 

No one was seen in Ogonowski’s video outside of their vehicles.

"It’s important to remember that during rut, bulls are on high alert and can get aggravated easily! No matter what time of year, always stay further than 25 yards away from all wildlife," the park wrote on August 19. 

This story was reported from Detroit. The Associated Press and Storyful contributed.