A tourist has been seriously injured by a bison in the second attack in three weeks at Yellowstone National Park.
The 62-year-old Australian was tossed into the air several times.
He was flown by helicopter to a hospital with serious but not life-threatening injuries.
Several visitors crowded the bison as it lay on the grass, with one taking photos with an electronic notepad just 3-5 feet away, said a Yellowstone spokesman.
"The bison was already getting agitated," Yellowstone spokesman Amy Bartlett said.
Park officials recommend getting no closer than 25 yards to a bison, which can weigh as much as a small car and run three times faster than a person.
It was the second bison attack in Yellowstone since the beginning of the summer tourist season a month ago when a 16-year-old girl from Taiwan was gored as she posed for a picture near the animal May 16.
