This footage shows a large female grizzly bear building her den as she gets ready to hibernate during the cold Alaskan winter and a conservationist at the animal sanctuary where it was shot said "our brown bears love to make their own".

The footage was shared online by the Alaska Wildlife Conservation Center, who captioned it: "Patty prepares her den! Every year our bears choose a suitable spot for their den inside their vast AWCC habitat. Most of the time, all three brown bears Patty, JB and Hugo share their winter bed together."

The female bear, Patron affectionately known as Patty is a rescue bear who lost her mother when she was still a cub and she now lives at the conservation centre, which is located in the ghost town of Portage, some 47 miles outside of the Alaskan capital Anchorage.

Winter is coming and brown bears (Ursus arctos horribilis), also known as grizzly bears in North America, are getting busy building their dens as they prepare to hibernate so they can make it through the harsh Alaskan winter.

The footage shows Patty prepping her den and Nicole Geilsa, a spokesperson for the conservation center, who also filmed this footage, told Clipzilla in an exclusive interview: "This fun video highlights AWCC’s resident Brown Bear, Patron, prepping her den for the long winter’s nap ahead."

She added: "Here at AWCC, we often get asked if our bears dig their own dens. While our black bears have dens we’ve made for them, our brown bears love to make their own. In the wild, brown bears typically dig new dens every year.

"The den entrance is just large enough for the bear to squeeze through so it will cover quickly with insulating snow. The chamber is dug only slightly larger than the bear’s body to allow for maximum heat retention.

"While asleep in their dens, their heart rate, respiration, and body temperature drop, but brain activity continues in bears throughout the winter and they can be easily woken up. Instead of true hibernation, a bear’s winter rest is actually called ‘torpor’."

The Alaska Wildlife Conservation Center describes itself as "a nonprofit sanctuary dedicated to preserving Alaska’s wildlife through conservation, education, research and quality animal care."

Nicole said that they take in orphaned and injured animals all year round and provide them with a home for the rest of their lives. She said that the sanctuary maintains over 200 acres of spacious land so that all of the animals can truly feel at home and behave as they would in the wild.

She said that this was important because the animals also act as "education ambassadors" for their species.

Nicole also said that it was not at all uncommon for visitors to see "brown bears swimming, moose strutting, wood bison roaming, muskox playing, wolves posing, porcupines climbing, and more."

The animal sanctuary explained that Patty, who is JB's sibling, lost her mother when she was still a cub when a local shot her after she killed a moose calf in his backyard.

Fearing that the bear might go for his dog, the man, unnamed, killed Patty's mother, not realising that she had two cubs.

As soon as he realised his mistake, he called a local wildlife biologist who as a former gymnast managed to retrieve Patty and JB from a treetop that they have climbed to hide in.

The cubs were handed over to the animal sanctuary in 2004 and have "since thrived!"

Visitors can often see them digging holes in the ground or catching fish in the nearby stream.

Grizzly bears typically hibernate for 5 to 7 months every year, emerging in March or April with the arrival of spring. But with climate change, they are increasingly emerging from their torpor in January and February, which can be problematic as their food supplies are often scarce at that time of year.