A woman visiting Yellowstone National Park learned the hard way why people should not try to pet the bison.

Video shows a tourist attempt to pet a bison grazing by a pathway May 20 after a group approached the animal to take selfies.

When the woman reached out to pet the big bovine, she got quite the scare. The bison lowered its head and lunged at her with its horns. The animal snagged the tourist's sweater as she scrambled to get away, but she managed to break loose and appeared unharmed.

The incident shows exactly why people should not get too close to wild animals, according to Zoo Miami ambassador Ron Magill.

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Tourists attempt to take selfies with a bison at Yellowstone National Park

Tourists approached a bison at Yellowstone National Park May 20, disobeying park guidance. (ViralHog)

"You know, people look at them. They think it looks like a big brown hairy cow. 'I want to take a picture because I've seen all the pictures with the bison,'" Magill told Fox Weather. "I credit a lot of this stuff to social media – people who want to get that selfie. They want to get more likes, and they might not realize they are going to end up in the hospital."

Bison are the largest land mammals in North America, can run up to 35 mph and can turn on a dime, Magill added.

Yellowstone authorities say visitors to the park should stay at least 25 yards away from bison for their own safety. But Magill suggested some people ignore the guidelines in pursuit of likes on social media.

"They're taking their phones out. They're trying to pose. They're turning their backs to a wild animal. I don't know what they're thinking," Magill told Fox Weather. "Now, the calving season comes along, the females are going to be very protective of their calves."

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A woman attempts to pet a bison on the head.

A woman tried to pet the bison.  (ViralHog)

The males can be especially territorial and aggressive during rutting season, Magill said. After watching the video, Magill said the bison's body language made it clear he was upset. 

"When a tail goes up on a bison, that is bad news, guys, really bad news," Magill said. "This woman actually looked like she was going to go pet that animal. I don't know what she's thinking. It's like people think they're at Disney World."

Interfering with wildlife at national parks not only threatens human safety but also can harm the animals. Just last week, the Yellowstone staff euthanized a newborn bison calf after a man touched it, causing the herd to reject the baby. 

The National Park Service reminded tourists not to interfere with the animals.

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A tourist scrambles away from a bison after it lunged at her

The bison lunged at the woman, nearly goring her and causing her to stumble away.  (ViralHog)

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"The safety of these animals, as well as human safety, depends on everyone using good judgment and following these simple rules," it said.

Fox News' Julia Musto contributed to this report.