Bears Make Great Astronauts – Their Bones Remain Strong through Hibernation


Humans’ and most animals’ bones become weak and brittle when not used regularly. Without the application of external force, bones do not get the signal to grow and develop. Putting a cast on a broken bone immobilizes the limb, allowing the break to heal, but the resulting lack of stimulus actually makes the bone much weaker in the end. This is especially notable in elderly people, who can end up bedridden for the remainder of their days after suffering a single broken bone. Loss of bone strength is also a serious problem for astronauts, who remain in the zero gravity environment of outer space for extended periods of time. However, a study shows that the American black bear, which spends half the year hibernating, does not show any loss in bone density or bone strength after hibernation, despite being almost completely inactive during that period. Rather, the bears’ bones actually become stronger, and remain strong even into old age.

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With a better understanding of the mechanism that allows bone development without external force, people of the future will be able to frequently venture out into space without worry of osteoporosis or loss of bone strength. Furthermore, it may be possible to combat the root cause of osteoporosis and prevent the bone degeneration that presently occurs during injury recovery, without the need for drugs.

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