Old man throwing rams skyward in Yellowstone

A bull bison, said to weigh 2,000lb (900kg), charged at an elderly man and head-butted him, knocking him into the air in Wyoming’s Yellowstone National Park.

Viral footage of the incident shows a boy and his grandfather snapping a photo of the buffalo lying in the grass, before the giant animal jumps on his feet and chases him.

The man, identified by US media as Carl Isom-McDaniel, 65, suffered multiple injuries and was described by eyewitnesses as being in “extreme pain”.

He was sent to the hospital, the New York Times reported. The National Park Service (NPS) has not released any information about the attack.

The BBC has asked the NPS for comment.

“Bison may seem quiet, but these large animals have injured more people than any other animal in Yellowstone,” the organization says on its website.

“They can run 3x faster than humans, which makes it very important to give them plenty of space.”

The NPS recommends that Yellowstone visitors stay at least 25 yards (23m) from bison at all times and “do not approach bison to take photographs.”

The incident happened in the final hours before sunset on Friday evening at the Bridge Bay Campground near Yellowstone Lake.

When Isom-McDaniel and her grandson appeared far away from the animal, their feet were slow and they picked up their cameras to take a picture.

The buffalo squirms repeatedly on its side in frustration before springing to its feet.

A white car slowly approaches the scene, but the driver speeds off after the buffalo fills the car. The animal continues onward, leaving behind a cloud of waste as it barrel toward Isom-McDaniel and his grandson.

The couple tried to escape the bison by running through a thicket of trees, but the animal eventually caught Isom-McDaniel.

Mike McLeod, who reported on the incident, told local paper Cowboy State Daily, “The bison hooked his left horn on his hip and threw him in the air.” “He did a perfect flip and landed on his side.”

MacLeod continued: “He was very sore in his leg, and otherwise he was alert the whole time, in good spirits, he joked.”

According to the NPS, winter is the busiest season in Yellowstone. About 60% of the annual visitation occurs only in the months of June, July and August.

July coincides with the animals’ mating season — a period of “peak breeding” when testosterone levels rise among bulls, said Jennifer Barfield, director of science at the Laramie Futiles Bison Conservation Herd in Colorado.

“This really pushes their behavior, and they can be more unpredictable than other times of the year,” said the Colorado State University professor.

Barfield said her team stays away from buffalo during mating season, except to make observations on vehicle safety.

For pedestrians, “it’s always good to remember that 25 yards is the minimum safe distance,” she said.