Respiratory System
A polar bear's respiratory system is similar to that of any other mammal. The respiratory system uses the lungs, blood, heart, veins and arteries to take in oxygen, transport it around the body and breathe out carbon dioxide. A polar bear can close off its nose, in order to stop water from entering it when swimming. To enable the polar bear to stay under the water for around three minutes at a time, the polar bear has large lungs.
The illustration shows a polar bear breathing underwater and blowing an air bubble.
The illustration shows a polar bear breathing underwater and blowing an air bubble.