Polar bears are one of the largest canivores in the world. Polar bears have blubber under their fur. Polar bears have a long neck and a narrow skull that helps the polar bear swim under water. Polar bears's front feet are flat and large. Polar bears can wiegh 400 to 700 kg. Polar bears are twice as large as lions and tigers. Polar bear babies are 30 to 35 cm long and weigh 450 grams.