A jogger was attacked and injured by a grizzly bear while running on a backcountry trail on the west side of Glacier National Park early Sunday morning.

Thomas Nerison, 60, of Kalispell, told park officials he was bitten by a grizzly at about 9:45 a.m. while running on the Lake McDonald Valley Trail. He suffered non-life-threatening injuries and was able to drive himself to Kalispell Regional Medical Center for treatment.

Nerison told an investigating ranger that he was running northeast on the trail about one to one-and-a-half miles from the Avalanche Lake trailhead when he heard what he described as the sound of a dog barking and then galloping horses coming up the trail behind him, park spokeswoman Amy Vanderbilt said in a press release late Monday.

Nerison said he was not making any noise on the trail and did not have bear spray with him. He had just enough time to turn around and get off the trail about a foot when he saw what he estimated to be two 250-pound grizzly bears running toward him.

Nerison said he believed the bears were running from something that had startled them. One of the bears stopped close to him. He told rangers he kicked the bear and then fell down. At that point the bear bit him twice as he continued to kick.

Nerison said he used sticks to poke at the bear and the bear lost interest in him, moved back toward the way it had come and then went uphill and away from the trail.

Nerison then walked downhill and cross-country to Going-to-the-Sun Road, where he got a ride from a visitor back to his own car at the Avalanche trailhead. He drove himself to the hospital emergency room for treatment.

During an interview after the incident, Nerison told a ranger he normally carries bear spray but didn't have spray with him when he encountered the bears.

On Sunday afternoon, rangers closed the trail between the junction with the Avalanche Trail and the Johns Lake Trail. Park rangers are investigating the incident.

The park is seeking information from anyone who may have been on the Lake McDonald Valley Trail on Sunday between 9 and 10 a.m. Contact park headquarters at 888-7801 if you were on the trail or might have seen bears or dogs in the area between Johns Lake Trailhead and Avalanche Trailhead.

Running on trails and traveling alone in grizzly bear country is not recommended in Glacier Park, Vanderbilt said. Trail running is discouraged because there have been an increasing number of injuries and fatalities nationwide due to runners surprising bears at close range.

"Make no mistake, bears are active," Park Superintendent Chas Cartwright said. "All park visitors should be alert while bicycling or simply walking and/or driving along park roads."

Cartwright said visitors should be knowledgeable about how to use bear spray and have it readily accessible and not stowed away in a pack.

Sunday's incident is the first bear-related injury in Glacier since August 2005.

In June 1996, a 70-year-old man sustained injuries from a grizzly bear while he was hiking alone on the same trail.

Park visitors are asked to report all sightings (or signs' of bears and/or mountain lions by stopping by or calling park headquarters at 888-7800 to report bear and mountain lion sightings as soon as possible.

More information about safety in bear country is available on the park's Web site at www.nps.gov/glac/planyourvisit/bears.htm.