December is upon us, and although the winter solstice is still three weeks away, temperatures here in Scottsdale are dropping. Believe it or not, it gets cold in the desert! The foxes, coyotes, and wolves all have their winter coats, and Goliath the tortoise spends much of his time in the sun or inside his brand new heated den.
Many visitors ask our Trail Guides if our five black bears hibernate in the wintertime. The short answer is yes; but it’s not quite that simple!
Black bears do hibernate, but their hibernation differs significantly from that of smaller mammals. Consider the chipmunk for comparison. Chipmunks (and other small mammals) lower their body temperature to near freezing during hibernation, then raise it every few days to wake, eat, and eliminate waste. They then lower their body temperature again and repeat the cycle. Black bears do not lower their body temperature during hibernation; in the wild they lower their heart rate as well as their metabolism, surviving off stored fat as they sleep up to 7 months out of the year!
The amount of time spent hibernating varies based on their environment. If there is easy access to food and water in the wintertime – like there is in our wildlife sanctuary – bears will hibernate for a shorter period. Prior to recent studies, many names were coined for the black bear’s unique hibernation qualities: torpor, winter sleep, dormancy, and “carnivorean lethargy.” Leading physiologists now simply call it hibernation (North American Bear Center).
The five black bears at SWCC (Tahoe, Igasho, Grizz, Cinnamon, and Heavenly) do not enter a period of full hibernation, since they have continuous access to food, water and medical care thanks to generous donors like you. Although they’re technically experiencing a period of hibernation, our Animal Care specialists describe their higher than usual levels of activity during the coldest months of the year with the word “torpor.”