Although polar bear cubs may be prey to other arctic carnivores, such as wolves, the only animals to naturally predate on adult polar bears and cubs are other polar bears. Cannibalism among polar bears is generally a result of extreme hunger, and mothers have been known to eat their own young. Male polar bears may also kill other male polar bears in competition for mates.
Humans have also hunted polar bears for thousands of years, whether for food, fur or ritual. Despite government regulation and outright bans in Norway and some parts of Russia, hunting by humans is the primary cause of polar bear deaths. Reasons for modern hunting include food, fur and protection of human life and property.
Although Inuit people consume polar bear meat and use bear fur, the greatest threat humans pose to polar bears comes from habitat destruction. Male polar bears sometimes eat baby polar bears for unknown reasons to scientists. Only 42 percent of polar bear cubs that live in Alaska reach a year of age, as of 2006.