seven months

The black bears of Alaska spend up to seven months in hibernation every year, without eating, drinking, urinating or defecating, and when they emerge from their slumber, it is as if nothing had happened. They are in practically the same physiological condition as when they entered hibernation.

• Alok Jha, science correspondent
• guardian.co.uk, Thursday 17 February 2011 19.00 GMT
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