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
Flat-spired three-toothed snail among 40 species of tridopsine snails in eastern North America. Populations were divided into family trees showing the phylogenetic relationships among 18 groups of species. Nine of these groups consisted of a single species, of which "Triodopsis platysayoides" was one group. This species of snail is endemic to the United States. The flat-spired three-toothed snail is found only in West Virginia, among Upper Connoquenessing sandstone outcroppings and boulders, in a restricted area along the rim of the Cheat River gorge. The U.S. Fish and Wildlife Service considers this snail to be threatened since 1978. Little is known about the life