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Phocids
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 E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinniped
Pinnipeds (pronounced ), commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. 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). 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 evidence supports them as a monophyletic lineage (descended from one ancestral line). 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. Seals range in size from the and Baikal seal to the and southern elephant seal male, which is also the largest member of the order Carnivora. Several species exh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Lion
Sea lions are pinnipeds characterized by external ear flaps, long foreflippers, the ability to walk on all fours, short and thick hair, and a big chest and belly. Together with the fur seals, they make up the family Otariidae, eared seals. The sea lions have six extant and one extinct species (the Japanese sea lion) in five genera. Their range extends from the subarctic to tropical waters of the global ocean in both the Northern and Southern Hemispheres, with the notable exception of the northern Atlantic Ocean. They have an average lifespan of 20–30 years. A male California sea lion weighs on average about and is about long, while the female sea lion weighs and is long. The largest sea lions are Steller's sea lions, which can weigh and grow to a length of . Sea lions consume large quantities of food at a time and are known to eat about 5–8% of their body weight (about ) at a single feeding. Sea lions can move around in water and at their fastest they can reach a ... [...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 Mustel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walrus
The walrus (''Odobenus rosmarus'') is a large pinniped, 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 (biology), 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 zone, benthic bivalvia, bivalve mollusks to eat. Walruses are relatively long-lived, social animals, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otariids
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 Mustelo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical region. Italy is also considered part of Western Europe, and shares land borders with France, Switzerland, Austria, Slovenia and the enclaved microstates of Vatican City and San Marino. It has a territorial exclave in Switzerland, Campione. Italy covers an area of , with a population of over 60 million. It is the third-most populous member state of the European Union, the sixth-most populous country in Europe, and the tenth-largest country in the continent by land area. Italy's capital and largest city is Rome. Italy was the native place of many civilizations such as the Italic peoples and the Etruscans, while due to its central geographic location in Southern Europe and the Mediterranean, the country has also historically been home ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquitanian (stage)
The Aquitanian is, in the ICS' geologic timescale, the oldest age or lowest stage in the Miocene. It spans the time between 23.03 ± 0.05 Ma and 20.43 ± 0.05 Ma (million years ago) during the Early Miocene. It is a dry, cooling period. The Aquitanian succeeds the Chattian (the youngest age of the Oligocene) and precedes the Burdigalian. The Aquitanian Age overlaps with the Harrisonian, Agenian, Pareora, Landon, Otaian, and Waitakian Ages from various regional timescales. Stratigraphic definition The Aquitanian Stage was named after the region Aquitaine in France and was introduced in scientific literature by Swiss stratigrapher Karl Mayer-Eymar in 1858. The base of the Aquitanian (also the base of the Miocene Series and the Neogene System) is defined as the place in the stratigraphic column at the first appearance of foram species ''Paragloborotalia kugleri'', the extinction of calcareous nanoplankton species ''Reticulofenestra bisecta'' (which forms the base of nanoplankton b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noriphoca
''Noriphoca'' is an extinct genus of phocid belonging to the subfamily Monachinae. It is known from the late Oligocene to early Miocene of Italy. Species The type species of ''Noriphoca'', ''N. gaudini'', was originally named ''Phoca gaudini'' on the basis of a skull from late Oligocene to earliest Miocene deposits in Chiento, Italy. Later authors referred it to either ''Monotherium ''Monotherium'' is an extinct genus of phocid belonging to the subfamily Monachinae. It is known from fossils found in the middle to late Miocene of Belgium. Species The type and only species of ''Monotherium'' is ''M. delognii'', described from ...'', '' Pristiphoca'', or the physeteroid genus '' Paleophoca''. However, it was later shown that ''P. gaudini'' cannot be referred to ''Monotherium'' as the latter was probably phocine and not monachine, and erected ''Noriphoca'' for the stem-monachine species ''P. gaudini''. References {{Taxonbar, from=Q53014899 Miocene pinnipeds Prehistoric ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Seal
The freshwater seals are seals which live in freshwater bodies. The only exclusively freshwater seal species is the Baikal seal, locally named (). The others are the subspecies or colonies of regular saltwater seals. These include two subspecies of ringed seal: the Ladoga seal and the Saimaa ringed seal. Common seals (harbor seals) are known to enter estuaries and freshwater rivers in pursuit of their prey. Colonies of common seals live in some lakes, such as seals of Iliamna Lake, Alaska, trapped there a long time ago. There is also a subspecies called the Ungava seal (''Phoca vitulina mellonae'') that comprises less than 300 individuals landlocked in the fresh water of Lacs des Loups Marins, Petit Lac de Loups Marins, and Lac Bourdel in northern Quebec. California sea lions can also live in fresh water for periods of time, such as near Bonneville Dam, nearly up the Columbia River. In 2004, a healthy sea lion was found sitting on a road in Merced County, California, almost a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baikal Seal
The Baikal seal, Lake Baikal seal or (''Pusa sibirica''), is a species of earless seal endemic to Lake Baikal in Siberia, Russia. Like the Caspian seal, it is related to the Arctic ringed seal. The Baikal seal is one of the smallest true seals and the only exclusively freshwater pinniped species.Randall R. Reeves, Brent S. Stewart, Phillip J. clapham, James A. Powell, ''"National Audubon Society Guide to the Marine Mammals of the World"'', Alfred A. Knopf publishing, New York, 2002 A subpopulation of inland harbour seals living in the Hudson Bay region of Quebec, Canada (Lacs des Loups Marins harbour seals), as well as the Saimaa ringed seal and the Ladoga seal (both ringed seal subspecies), are also found in fresh water, but these seals are part of species that also have marine populations. The most recent population estimates are 80,000 to 100,000 animals, roughly equaling the expected carrying capacity of the lake. At present, the species is not considered threatened. Descrip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperate
In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout the year and more distinct seasonal changes compared to tropical climates, where such variations are often small and usually only have precipitation changes. In temperate climates, not only do latitudinal positions influence temperature changes, but sea currents, prevailing wind direction, continentality (how large a landmass is) and altitude also shape temperate climates. The Köppen climate classification defines a climate as "temperate" C, when the mean temperature is above but below in the coldest month to account for the persistency of frost. However, other climate classifications set the minimum at . Zones and climates The north temperate zone extends from the Tropic of Cancer (approximately 23.5° north latitude) to the Arctic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
