Polar bears cannot be kept as pets because they are an endangered species. It is illegal to personally own, buy, or sell an animal that is classified as an endangered species.
Polar bears were added to the endangered species list in 2008. As of 2015, the current polar bear population is between 20,000 and 25,000 and in decline, as climate change has forced them to adapt to a changing habitat. They are the first animal species to be listed as endangered for the sole reason of global warming. Polar bears can be sponsored through some wildlife foundations and activist groups, such as the World Wide Fund for Nature.