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
Spade-toothed whale initially remained undescribed, but was later believed to be from a ginkgo-toothed beaked whale. In 1986, a damaged calvaria was found washed up on Robinson Crusoe Island, Chile, and was described as a new species, "Mesoplodon bahamondi" or Bahamonde's beaked whale. In December 2010, two specimens, a cow and calf, were found stranded on Opape Beach, Bay of Plenty, New Zealand. They were originally identified as Gray's beaked whale, but later genetic analysis revealed that they represented the first complete specimens of the spade-toothed whale. Following this find, a report describing the spade-toothed whale and an analysis of their DNA