Polar Bear
A habitat where the average winter temperature can reach –40°F (–40°C) isn't exactly ideal for raising young, so the mother polar bear digs an underground den where she remains in a hibernation-like state through the coldest winter months. The mother gives birth between November and February to a litter that almost always consists of two cubs, who then live in the safety of the den while nursing on the fasting mother's milk. At the end of this period, the bears emerge from the den and eventually make their way to moving sea ice, where the mother can catch seals once again. At this point, the mother has been fasting for up to eight months while raising two hungry cubs.

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