A hiker who set out alone outside the Mammoth Hot Springs area on Friday morning was badly injured in an encounter with a grizzly bear.

Yellowstone National Park sent out word within hours of the incident that a 39-year-old male was able to walk out under his own power after the mauling. The man was about 1.5 miles down the Beaver Ponds Trail from the trailhead when he encountered what was believed to be two grizzlies.

“One bear made contact with the hiker and he sustained significant injuries to his lower extremities,” Yellowstone’s notice said.

The man was transported to the Livingston Hospital by a National Park Service ambulance. The 6-mile-long Beaver Ponds Trail, which is heavily trafficked, is also closed until further notice.

This is the first person injured by a grizzly bear inside Yellowstone during 2021, though there have been other maulings in the ecosystem. In April, 40-year-old Charles “Carl” Mock, of West Yellowstone, Montana, died as a result of complications from injuries sustained from a male grizzly that was defending a moose carcass. The grizzly was later killed by wildlife officials investigating the attack.

Best practices for recreating in grizzly country include hiking in groups of three or more, carrying bear spray, making noise and staying alert.

Yellowstone’s public affairs office said Friday there were no additional details about the injured hiker to share at this time.