Just like disturbances wake you up, they wake up the animal kingdom -- often with dire results.
Hibernation, simply, is a state of inactivity in animals. It is typically characterized by a drop in metabolic activity—a physical slowing of the body—in addition to lower body temperature and slower breathing.
Indeed, hibernation is a sleep deeper than most humans could imagine, but it is not impervious to interruption. Increasingly, changes brought into nature by the modern world are unsettling hibernating animals during a time of the year when they are most vulnerable.
One animal that truly hibernates is the European hedgehog
. Though hibernation periods among animals vary from a few days to a few weeks, most settle down during winter, when normal food supplies are limited.
To survive this long period of inactivity, animals must spend the rest of the year building fat reserves that can supply energy during hibernation.
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