Marine biology gannets, and auks. Although they spend most of their lives in the ocean, species such as gulls can often be found thousands of miles inland. There are five main types of marine mammals, namely cetaceans (toothed whales and baleen whales); sirenians such as manatees; pinnipeds including seals and the walrus; sea otters; and the polar bear. All are air-breathing, and while some such as the sperm whale can dive for prolonged periods, all must return to the surface to breathe. Marine habitats can be divided into coastal and open ocean habitats. Coastal habitats are found in the area that extends
Greater white-toothed shrew but otherwise very similar, and can often be distinguished only by close inspection of its teeth which are unpigmented. The greater white-toothed shrew is distinguished by a careful examination of their unpigmented teeth. Like other "white toothed-shrews", "C. russula" lacks the deposition of iron in their enamel at the tips of their teeth This particular species has a greyish or reddish brown upper coat with a yellowish grey coat in the underside The greater white-toothed shrews are part of the medium-sized shrews and weigh around 11 grams to 14 grams The head and body length of "C. russula" is about