True polar bear habitat encompasses only a thin strip of the land and extends far out onto the sea ice, depending on the season and latitude. They utilize the shorelines of islands and mainland during the ice-free months of the summer and early fall before heading out on the ice to begin their seal hunt. In spring and early summer, most come ashore as the ice melts, to spend the summer in a lethargic, almost hibernating state, lounging about, staying cool and conserving energy. But there are a number of High Arctic bear residents that stay year-round on the polar ice cap. Unfortunately global warming is drastically reducing the extent of this ice cap, threatening this bear population.
Denning is done in the winter, when a pregnant female digs a shallow cave-like den, usually on the leeward side of a steep embankment that’s piled deep in a snow drift. Here she will bear her offspring, emerging in March. She then heads out on the ice with the cubs of the year to try to feed as much as possible before meltoff.
Since their habitat lies in one of the coldest regions on Earth, they are wonderfully adapted to low temperature. Several major factors contribute to this adaptation. See Polar Bear Adaptations.
For one of the best works on polar bear adaptations and evolution, read Canadian polar bear researcher Dr. Ian Stirling’s book Polar Bears. You can find the book on Amazon – clicking on the link below will open in a new window.