5 Stages of Activity and Hibernation

The annual cycle of black bear activity and hibernation has five stages:   1.  hibernation   2.  walking hibernation   3.  normal activity   4.  hyperphagia   5.  fall transition…

Read More »

Digging a Den

Before researchers from the Wildlife Research Institute videotaped 3-year-old June digging this den in Eagles Nest Township, Minnesota, they had no idea some bears made dens so early—July 19, 2004….

Read More »

Do Black Bears Hibernate?

Short answer: yes. When people defined hibernation simply in terms of temperature reduction, bears were not considered hibernators. However, when biologists discovered the many metabolic changes that let black and…

Read More »

Heat Loss in Dens

In 2003, the BBC phoned researchers for help with a documentary using new thermal imaging technology. The telephone conversation sounded something like: BBC: “We’re looking for someone dumb enough to…

Read More »

How Do Chipmunk and Black Bear Hibernation Differ?

Chipmunk hibernation  Black bear hibernation  Preparation Eastern chipmunks (Tamias striatus) store food in a burrow system. Preparation Black bears (Ursus americanus) store body fat. Den temperature Temperatures remain mostly above…

Read More »

Will Snow Accumulate on a Black Bear’s Back?

Yes, snow accumulates on black bears at ambient temperatures below approximately 19 degrees Fahrenheit.  The photo shows a 3-year-old female black bear in an open den.  The temperature is 9…

Read More »

Whiteheart Den Cam

In fall 1999, Whiteheart gave researchers and the public the first views of how bears behave in the darkness of their dens when no one is around. Whiteheart denned 120…

Read More »

The Cub Probe

The cub probe is an Aqua-Vu Infra-red Underwater Camera donated by Jeff Zernov of Nature Vision, Inc. (Baxter, MN) and adapted for den use by TV producer Doug Hajicek. It…

Read More »

Researcher Discovers Clues to Bear Bone Strength

Science Daily, Dec. 29, 2003. From Journal of Experimental Biology, Vol 206. Inactivity is a prime cause of osteoporosis in most animals, including humans. A notable exception is the black…

Read More »

Hibernating Bears Conserve Muscle Strength

Science Daily (Apr. 25, 2007) — A new study measured strength and endurance of hibernating black bears. T.D. Lohuis and his coauthors found that black bears in hibernation lose only…

Read More »

Strong Arm Tactics

New Scientist News Service, February 21, 2001, Andy Coghlan Bears hardly lose any muscle when they hibernate, say zoologists at the University of Wyoming. Their findings could lead to new…

Read More »

Bears’ Mysterious ‘Fecal Plug’

The fecal plug has long been one of the mysteries of bear hibernation. Early observers described it as a dense plug of unidentified material, fibrous plant material, and bear hair….

Read More »