A black bear chased down and mauled a bicyclist on a mountain trail in Canada's most popular national park, the park's warden said.

The bear was later shot to death, and the cyclist was being treated for severe arm injuries at Foothills Hospital in Calgary, with reconstructive surgery in his biceps and triceps scheduled Monday.

Authorities said Greg Flaaten, 41, a Web administrator for the town of Banff, was attacked by the bear Friday evening along the heavily wooded Hoodoos-Bow River Trail in Banff National Park.

"We heard he had been chased on the bicycle for a while," said Ian Syme, the park's chief warden.

Shortly after the attack, two people on the trail spotted Flaaten's bike and a broken helmet and heard him calling for help. The bear was still pacing the area, so they called in the warden, who killed the animal.

Syme said the bear was about 140 pounds, much lighter than a normal, healthy bear.

Predatory attacks by bears are rare — 95 percent of the time the bear runs away, Syme said. Those that do occur are almost always in self-defense or a female bear defending her cubs, he said.