Polar bears can run as fast as聽40 kilometers per hour鈥攂ut only for short distances. Younger, leaner bears are the best runners and are able to聽cover two kilometers without stopping. Older and聽larger bears, on the other hand,聽quickly overheat.聽This overheating phenomenon is very common in聽polar bears, as they expend more than twice the energy聽of most other mammals when walking or running鈥攕howing higher than average increases in temperature and oxygen consumption.
