A park visitor was attacked by a grizzly bear and hiked miles to safety with severe facial injuries, park officials said.
The man, in his late 50s, was taking photographs of bears Wednesday when he was attacked, according to a statement from the park. He told rangers he had been attacked by a sow with a cub.
After the attack, he hiked 2 to 3 miles (3 to 5 kilometers) and was discovered by other park visitors around 1 p.m., the statement said. He was hospitalized, but officials declined to release his condition Wednesday evening.
"I was told that the injuries to his face were severe," Yellowstone spokesman Al Nash said, adding that the injuries were the type that result from clawing.
Park officials will investigate the attack, Nash said.
Grizzly bears and black bears, including sows with cubs, are active in the spring, Park Service officials said. Park visitors are encouraged to travel in groups, make noise and carry pepper spray.
No human injuries from bears were reported in Yellowstone last year, and only eight minor injuries have been reported since 2000, the Park Service reports. The last bear-caused human fatality in the park was in 1986.