A pair of bears appeared after the longest hibernation period ever at the ski resort in British Columbia where they live.

The bears, named Grinder and Coola, have lived in a sanctuary on a mountain in North Vancouver since 2001.

171 days, this was their longest winter dormancy period in 21 years, according to Grouse Mountain Resort staff in a press release. The staff said the bears were "greeted with cheers" when they emerged from their den on Thursday morning. This is the second consecutive year their winter hibernation broke a record.

Last year, the bears, who usually hibernate for four months, rested for 170 days. Before that, it was 153 days.

Veterinarian Ken Mackestin, director of the wildlife sanctuary and veterinarian, said in a press release: "Winter hibernation is a natural way to conserve energy during a time of reduced food availability." During this time, they are monitored by staff using video cameras and infrared.

Grinder and Coola were found separately as orphaned cubs in 2001 and live in a 5.5-hectare sanctuary at the top of Grouse Mountain.

The bears' living area contains an advanced camera monitoring all their movements so the public can observe their actions, but the wildlife sanctuary is also a tourist attraction. A video clip from the outdoor camera Friday morning showed one of the bears lingering around its fence, which was still covered in snow.