BANFF, Alta. — A 41-year-old mountain biker attacked by a black bear in Banff National Park may have been mauled over a prolonged period of time, the park's chief warden said Saturday.

The unidentified Banff man, though seriously hurt in the attack, is in stable condition in hospital in Calgary after undergoing surgery Friday night, said Ian Syme, the chief warden for Banff National Park.

Two other cyclists biking along a thickly wooded mountainous trail east of the Rocky Mountain townsite on Friday evening discovered an unusual sight, said Syme.

"They actually didn't come across him, they came across his bike," Syme said in an interview.

The cyclists then heard a voice yelling to them from the woods nearby, he said.

"They heard him yelling for help, and (he) indicated he was being attacked by a bear."

Syme said the two cyclists then pedalled quickly to a nearby campground where they called a park warden, who was dispatched at around 8:15 p.m. along with an RCMP officer.

It took a warden and the Mountie about 15 minutes to find the man just off the trail in the woods, Syme said, but the bear was still pacing near the man and refused to leave the area.

"When they approached the victim the bear moved off slightly," he said. "While the RCMP attended the victim, the warden kept a very close eye on the bear. When it became apparent that it was not going to move off, he shot it."

The behaviour by the extremely thin young adult black bear was unusual, Syme said, because confrontations between bears and humans are usually brief, and the bear normally leaves the area after an attack.

"When the bear stays around and repeatedly attacks a person, it's no longer a surprise attack. There's some concern over it becoming a predatory attack," Syme said, who added there are fears the bear may have regarded the man as prey.

Syme estimated the bear weighed only about 63 kilograms - much less than the weight of a normal, healthy bear.

The victim was found a short distance from his bike, and there were dragging marks and signs of a struggle, Syme said, leading investigators to believe the attack was a prolonged one with the man remaining conscious throughout.

The victim hasn't yet been interviewed, Syme said, so officials don't know the circumstances of the attack, including whether he may have fallen off his bike and was attacked, or whether the bear may even have dragged the cyclist off the bike.

The mountain biker was wearing headphones at the time of the attack, a practice Syme said he doesn't recommend when hiking or biking in the mountain park.

He won't speculate on whether the man may simply not have heard the bear lumbering through the woods near the trail.

The area where the attack happened remains closed.

Last fall, a Calgary man survived a grizzly attack in the park while Isabelle Dube of nearby Canmore was fatally mauled by a grizzly last year while jogging with friends.