The elongated head and streamlined body of the polar bear help it in swimming. They can swim 4 - 6 miles per hour. Besides weathering extreme temperatures on land, polar bears go extreme off land too. Many polar bears spend a great amount of time in the water and on ice floes. Their body shape is more elongated and streamlined for swimming. Polar bears do not have the shoulder hump of the brown bear and so the neck is longer which helps keep the head above water.