"Bison may appear tranquil, but these large animals have injured more people in Yellowstone than any other animal," the National Park Service notes on its website.
A bull bison, weighing roughly 2,000lb, sprinted toward 65‑year‑old Carl Isom‑McDaniel and rammed him with its head, catapulting him several metres into the air.
The incident was captured on a handheld camera. A boy and his grandfather paused to snap a photo of the bison as it lay in the grass, then heard the animal hoard to its feet and began to chase them.
Witnesses described the man as "in a lot of pain" as he was thrown and later said he was conscious, joking, and in good spirits despite a bruised leg.
He was taken to hospital by the New York Times. The National Park Service has not released details of the attack; the BBC has requested a comment.
The National Park Service reiterates that bison can run three times faster than humans and that visitors should keep a safe distance of at least 25 yards (23m) and never approach a bison to take photos.
The event occurred on Friday evening at Bridge Bay Campground near Yellowstone Lake, during the final hour before sunset. The bison repeatedly flopped on its side in agitation, then launched itself toward the two hikers. A white truck approached, but the driver fled after the bison charged the vehicle.
The attack happened during July, the busiest month for Yellowstone visitors, and also coincides with the bulls’ mating season, a period when heightened testosterone makes them more unpredictable.
Jennifer Barfield, a scientist at the Colorado State University, warned that during the breeding period bison answer breeding behaviour and become harder to predict. She and her team maintain a safe distance from the animals in the field, while encouraging visitors to maintain the minimum 25‑yard distance on foot.
"That’s going to drive their behavior," Barfield told the National Park Service. "They’re going to be unexpectedly more aggressive or territorial than at other times of the year."
For visitors to Yellowstone, the latest incident underscores the importance of mindful behaviour around wildlife and following NPS safety guidelines to protect both humans and animals.



















