As of 2008, scientists estimate there are approximately 20,000 to 25,000 polar bears. Polar bears are considered endangered as their environments are at risk from climate change. This is primarily due to warming conditions that cause sea ice to melt.
Other known risks to the polar bears' existence include poaching, pollution and industrial issues, but rapid loss of sea ice is the major threat to their survival. Hunting is not regulated and is a persistent threat to polar bears.
To survive, polar bears must live in an arctic climate. They keep warm with two layers of fur, including a thick fat layer. They rely on high caloric food sources, especially seals. They often eat just the blubber of animals, leaving behind the carcass. Polar bears live an average of 15-18 years, longer if they are in captivity.