Another group that is classified by the order Carnivora are the polar bears and sea otters. These animals have a more primitive structure of a paw or padded foot, and they are marginally aquatic because they can spend some time in water, but most of their time is spent on land. Many of these animals go into the water to eat, and they play a large role in maintaining marine ecosystems in regulating populations of prey. There is no significant fossil record because these animals are thought to be recent entries into the aquatic environment (Uhen, 2007). Both polar bears and sea otters are covered in fur like most mammals, but they have adapted an oilier fur that is practically waterproof (Reidenberg, 2007). This adaptation allows the fur to
