How Do the Grizzly Bears at CMZoo Spend the Winter? As our 17-year-old grizzly bears, Emmett and Digger, prepare for the winter, they will start living at a much slower pace.
We often associate bears with hibernation, but science has shown that many animals, like raccoons, skunks, and bears, survive the winter using torpor instead, which is a much lighter form of hibernation. True hibernators include animals like chipmunks, ground squirrels and woodchucks. Animals in true hibernation remain in a low-energy state through the entire winter, and waking up takes a lot of time and energy for these animals.
Instead of this deep hibernation, grizzly bears enter into torpor, where they fall into a deeper-than-normal sleep during their inactive moments of the day, which conserves energy. When in the torpor state, they will also experience decreased breathing, heart rates, lower metabolic rates and a slightly reduced temperature. Bears are still intermittently active during the winter months but are able to sleep more than 100 days at a time without passing waste, eating, or drinking.
But do all bears go into torpor?
While there is still lots of ongoing research being done on bears, biologists have found that torpor behaviors tend to depend on location, climate, food supply in the wild and the individual bear. Certain bears in warmer climates will only spend two or three weeks in torpor. If bears have a lack of food supply, they will come out more often to find food.
When Emmett and Digger’s wild grizzly bear cousins up in Montana head into winter, they “den up,” or build a den with natural materials that they sleep in most of the winter. Emmett and Digger have access to their outdoor day beds year-round but also like to create their own dens throughout their yard in the winter.
They even cuddle with each other!
Emmett and Digger move a little slower in the winter, but are still active and captivating. They will casually splash in their pond, play-wrestle, and slowly explore their habitat. Keepers reward the grizzly bears with special treats like salmon, other meats and fruits for participating in husbandry training and shifting.
Emmett and Digger can often be seen snuggling together, investigating enrichment items, and training with keepers throughout the whole winter season. Visit them in Rocky Mountain Wild.