BANFF, Alta. — A cyclist mauled by a black bear on a mountain trail near this Rocky Mountain resort town was hunted down on his bike by the predatory bruin, the park's chief warden said Sunday.

"We heard he had been chased on the bicycle for a while," said Ian Syme.

"We're not sure how far that was. Certainly at the time when you are chased like that things can seem to be a lot longer than they might be, but apparently he was chased."

Greg Flaaten was airlifted to hospital in Calgary after the Friday night attack.

Syme said Flaaten was to undergo surgery.

"He had significant damage to tricep and bicep. I understand he probably had a broken scapula as well," he said.

"I think the big factor here is the artery that runs into the arm was not injured and therefore circulation to his lower arm is still happening.

"They're doing reconstructive surgery on the bicep-tricep area."

Family of the 41-year-old mountain biker could not be reached for comment.

It's believed he was mauled over a prolonged period on the heavily wooded Hoodoos-Bow River Trail east of the Banff townsite.

He was found around 8 p.m. by two other cyclists, who stopped when they spotted a bike and a broken helmet near the trail and then heard the victim calling for help.

Robert Earl said once he and fellow cyclist Robin Borstmayer realized the bear was between them and the victim, they knew they couldn't rescue him alone.

The pedalled to a nearby campground and called a park warden, who was dispatched along with an RCMP officer.

When they arrived, the bear was still pacing near Flaaten and refused to leave, forcing the warden to shoot it dead.

Syme said it's rare to see such a predatory attack, adding that 95 per cent of the time the bear runs away and if it attacks, it's doing so to protect itself or its cubs.

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

Flaaten was found a short distance from his bike, and there were dragging marks and signs of a struggle.

Syme said they haven't spoken to him yet and are waiting for test results on the bear to come back.

Flaaten was wearing headphones at the time of the attack.

Last June, 35-year-old Isabelle Dube was killed by a grizzly while she and some friends were out jogging while on a hiking trail.