Timelapse video shows Tundra, a 17-year-old grizzly bear nestling down into a cozy den to hibernate for the winter at the Denver Zoo. https://abcn.ws/2Xj9jyd | ABC News

Grizzly bear siblings Kachina & Kiona have been “beary” busy – digging out piles of dirt to construct their dens. Their most recent den-digging project was nearly 12 feet in length, as the two sisters worked in tandem! Grizzly dens in the wild are made up of an entrance, tunnel and chamber, where bedding material is placed. This is all in anticipation of entering a state of “torpor” – a mild form of hibernation that is clearly starting, as the girls are mostly groggy these days and fattened up f