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Pinniped
Pinnipeds (pronounced ), commonly known as seals, are a widely range (biology), distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammal, marine mammals. They comprise the extant taxon, extant family (biology), 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). There are 34 extant species of pinnipeds, and more than 50 extinct species have been described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular phylogenetics, molecular evidence supports them as a monophyletic lineage (descended from one ancestral line). Pinnipeds belong to the order Carnivora; their closest living relatives are Musteloidea, musteloids (Mustelidae, weasels, Procyonidae, raccoons, skunks, and red pandas), having diverged about 50 million years ago. Seals range in size from the and Baikal sea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Mammal
Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears. They are an informal group, unified only by their reliance on marine environments for feeding and survival. Marine mammal adaptation to an aquatic lifestyle varies considerably between species. Both cetaceans and sirenians are fully aquatic and therefore are obligate water dwellers. Seals and sea-lions are semiaquatic; they spend the majority of their time in the water but need to return to land for important activities such as mating, breeding and molting. In contrast, both otters and the polar bear are much less adapted to aquatic living. The diets of marine mammals vary considerably as well; some eat zooplankton, others eat fish, squid, shellfish, or sea-grass, and a few eat other mammals. While the number of marine mammals is small compared to those found on land, their roles in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earless Seal
The earless seals, phocids or true seals are one of the three main groups of mammals within the seal lineage, Pinnipedia. All true seals are members of the family Phocidae (). They are sometimes called crawling seals to distinguish them from the fur seals and sea lions of the family Otariidae. Seals live in the oceans of both hemispheres and, with the exception of the more tropical monk seals, are mostly confined to polar, subpolar, and temperate climates. The Baikal seal is the only species of exclusively freshwater seal. Taxonomy and evolution Evolution The earliest known fossil earless seal is ''Noriphoca gaudini'' from the late Oligocene or earliest Miocene ( Aquitanian) of Italy. Other early fossil phocids date from the mid-Miocene, 15 million years ago in the north Atlantic. Until recently, many researchers believed that phocids evolved separately from otariids and odobenids; and that they evolved from otter-like animals, such as ''Potamotherium'', which inhabited ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnivora
Carnivora is a Clade, monophyletic order of Placentalia, placental mammals consisting of the most recent common ancestor of all felidae, cat-like and canidae, dog-like animals, and all descendants of that ancestor. Members of this group are formally referred to as carnivorans, and have evolved to specialize in eating flesh. The order is the fifth largest order of mammals, comprising at least 279 species. Carnivorans live on every major landmass and in a variety of habitats, ranging from the cold polar regions to the hyper-arid region of the Sahara Desert to the open seas. They come in a very large array of different body plans in contrasting shapes and sizes. Carnivora can be divided into two subclades: the cat-like Feliformia and the dog-like Caniformia, which are differentiated based on the structure of their ear bones and cranial features. The feliforms include families such as the felidae, cats, the hyenas, the mongooses and the viverridae, civets. The majority of felifor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eared Seal
An eared seal or otariid or otary is any member of the marine mammal family Otariidae, one of three groupings of pinnipeds. They comprise 15 extant species in seven genera (another species became extinct in the 1950s) and are commonly known either as sea lions or fur seals, distinct from true seals (phocids) and the walrus ( odobenids). Otariids are adapted to a semiaquatic lifestyle, feeding and migrating in the water, but breeding and resting on land or ice. They reside in subpolar, temperate, and equatorial waters throughout the Pacific and Southern Oceans and the southern Indian and Atlantic Oceans. They are conspicuously absent in the north Atlantic. The words 'otariid' and 'otary' come from the Greek ' meaning "little ear", referring to the small but visible external ear flaps ( pinnae), which distinguishes them from the phocids. Evolution and taxonomy Morphological and molecular evidence supports a monophyetic origin of pinnipeds, sharing a common ancestor with Mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walrus
The walrus (''Odobenus rosmarus'') is a large flippered marine mammal with a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. The walrus is the only living species in the family Odobenidae and genus ''Odobenus''. This species is subdivided into two subspecies: the Atlantic walrus (''O. r. rosmarus''), which lives in the Atlantic Ocean, and the Pacific walrus (''O. r. divergens''), which lives in the Pacific Ocean. Adult walrus are characterised by prominent tusks and whiskers, and their considerable bulk: adult males in the Pacific can weigh more than and, among pinnipeds, are exceeded in size only by the two species of elephant seals. Walruses live mostly in shallow waters above the continental shelves, spending significant amounts of their lives on the sea ice looking for benthic bivalve mollusks to eat. Walruses are relatively long-lived, social animals, and they are considered to be a "keystone species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steller Sea Lion
The Steller sea lion (''Eumetopias jubatus''), also known as the Steller's sea lion and northern sea lion, is a near-threatened species of sea lion in the northern Pacific. It is the sole member of the genus ''Eumetopias'' and the largest of the eared seals (Otariidae). Among pinnipeds, only the walrus and the two species of elephant seals are bigger. The species is named for the naturalist Georg Wilhelm Steller, who first described them in 1741. The Steller sea lion has attracted considerable attention in recent decades, owing to significant and largely unexplained declines in their numbers over an extensive portion of their northern range in Alaska. Description Adult animals are lighter in color than most sea lions, ranging from pale yellow to tawny and occasionally reddish. Steller sea lion pups are born almost black, weighing around , and remain dark in coloration for several months. Females and males both grow rapidly until the fifth year, after which female grow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Elephant Seal
The southern elephant seal (''Mirounga leonina'') is one of two species of elephant seals. It is the largest member of the clade Pinnipedia and the order Carnivora, as well as the largest extant marine mammal that is not a cetacean. It gets its name from its massive size and the large proboscis of the adult male, which is used to produce very loud roars, especially during the breeding season. A bull southern elephant seal is about 40% heavier than a male northern elephant seal (''Mirounga angustirostris''), twice as heavy as a male walrus (''Odobenus rosmarus''), and 6–7 times heavier than the largest living mostly-terrestrial carnivoran, the polar bear (''Ursus maritimus'') and the Kodiak bear (''Ursus arctos middendorffi''),. Taxonomy The southern elephant seal was one of the many species originally described by Swedish zoologist Carl Linnaeus in the landmark 1758 10th edition of his ''Systema Naturae'', where it was given the binomial name of ''Phoca leonina''. John Edwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla ( cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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