When you think of a bear, you probably think of a large furry animal that lives in forests and mountains. But polar bears are different. Scientists refer to them as marine mammals.
The word marine describes something that’s connected to the sea. And that’s just what polar bears are. These enormous mammals inhabit the top of the Earth. They spend most of their lives either on sea ice or swimming below it in the Arctic Ocean. Sea ice is frozen ocean water that forms, grows, and melts in the ocean. Unfortunately, the amount of sea ice is shrinking.
