3/18/2023 0 Comments Purebasic file existsSeals mainly live in marine environments but can also be found in freshwater. They spend most of their lives in the water, but come ashore to mate, give birth, molt or escape from predators, such as sharks and orcas. They have a layer of fat, or blubber, under the skin to keep warm in the cold water, and, other than the walrus, all species are covered in fur.Īlthough pinnipeds are widespread, most species prefer the colder waters of the Northern and Southern Hemispheres. Some species are well adapted for diving to great depths. Pinnipeds have well-developed senses-their eyesight and hearing are adapted for both air and water, and they have an advanced tactile system in their whiskers or vibrissae. Otariids have visible external ears, while phocids and walruses lack these. By comparison, terrestrial locomotion by phocids is more cumbersome. Otariids and walruses have hind limbs that can be pulled under the body and used as legs on land. Otariids use their front limbs primarily to propel themselves through the water, while phocids and walruses use their hind limbs. Though not as fast in the water as dolphins, seals are more flexible and agile. They have streamlined bodies and four limbs that are modified into flippers. Several species exhibit sexual dimorphism. Seals range in size from the 1 m (3 ft 3 in) and 45 kg (99 lb) Baikal seal to the 5 m (16 ft) and 3,200 kg (7,100 lb) southern elephant seal male, which is also the largest member of the order Carnivora. Pinnipeds belong to the order Carnivora their closest living relatives are musteloids ( weasels, raccoons, skunks, and red pandas), having diverged about 50 million years ago. While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as a monophyletic lineage (descended from one ancestral line). There are 34 extant species of pinnipeds, and more than 50 extinct species have been described from fossils. They comprise the extant families Odobenidae (whose only living member is the walrus), Otariidae (the eared seals: sea lions and fur seals), and Phocidae (the earless seals, or true seals). Pinnipeds (pronounced / ˈ p ɪ n ɪ ˌ p ɛ d z/), commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals.
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