HIBERNATING bears have a unique ability to stop their bones from degenerating during long periods of inactivity, a finding that is stimulating the search for new treatments for osteoporosis.
In humans, rapid bone loss is the inevitable consequence of a lack of physical activity from whatever cause, maybe enforced rest or even space flight. Bone production decreases at such times, while the rate at which bone breaks down increases.
Most hibernating animals are similarly affected, but the black bear (
To work out how, Seth Donahue of Michigan Technological University in Houghton and his colleagues monitored markers of bone metabolism in the blood of five bears. They discovered that while bone breakdown does increase during hibernation, bone production remains constant and may even peak when the animal becomes active again (
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