Polar bears have adapted to a lifetime in the cold Arctic temperatures, from the texture of their fur to the way they reproduce and care for their young. They highly depend on sea ice which unfortunately makes them a very vulnerable species. The status of large carnivores such as polar bears are obvious indicators of ecosystem health. Polar bears are being studied to gain an understanding of what is happening throughout the Arctic. Polar bears at risk are often signs of something wrong somewhere in the arctic marine ecosystem.