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Eared seals
An Australian Sea Lion
An Australian Sea Lion
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Suborder: Caniformia
Superfamily: Pinnipedia
Family: Otariidae
Gray, 1825
Genera

Arctocephalus
Callorhinus
Eumetopias
Neophoca
Otaria
Phocarctos
Zalophus

The eared seals or otariids are marine mammals in the family Otariidae - one of three groupings of Pinnipeds. Chordates ( Phylum Chordata) are a group of Animals that includes the Vertebrates together with several closely related Invertebrates Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands The diverse order Carnivora (kɑrˈnɪvərə or sometimes /ˌkɑrnɪˈvɔərə/ from Latin carō (stem carn-) "flesh" + vorāre Caniformia, or Canoidea (literally " dog-like " are a Suborder within the order Carnivora. Pinnipeds ("fin-feet" lit "winged feet" or fin-footed mammals are a widely distributed and diverse group of semi-aquatic marine Mammals comprising John Edward Gray ( 12 February 1800 &ndash 7 March 1875) was a British zoologist. The genus Arctocephalus consists of eight of the nine species of Fur seal. The Northern Fur Seal, Callorhinus ursinus, is an Eared seal found along the north Pacific Ocean, the Bering Sea and the Sea of Okhotsk The Steller sea lion, Eumetopias jubatus, also known as the northern sea lion, is a Sea lion of the northern Pacific. The Australian Sea Lion ( Neophoca cinerea) is a species of Sea lion that breeds only on the south and west coasts of Australia. Otaria redirects here If you are looking for the continent in Magic The Gathering, see Otaria. The New Zealand Sea Lion ( Phocarctos hookeri) also known as Hooker's Sea Lion or Whakahao in Māori is a species of Sea lion Zalophus is a genus of the suborder Otariidae ( Sea lions and Fur seals, order Carnivora. Marine mammals are a diverse group of roughly 120 species of Mammal that are primarily Ocean -dwelling or depend on the ocean for food Pinnipeds ("fin-feet" lit "winged feet" or fin-footed mammals are a widely distributed and diverse group of semi-aquatic marine Mammals comprising They comprise 16 species in seven genera commonly known either as sea lions or fur seals, distinct from true seals (phocids) and walruses (odobenids). In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. A genus (plural genera from Γένος Latin genus "descent family type gender" is a low-level Taxonomic For other uses of the term "sea lion" see Sea lion (disambiguation. Fur seals are any of nine species of Pinnipeds in the Otariidae family The true seals or earless seals are one of the three main groups of Mammals within the seal Suborder, Pinnipedia. The walrus ( Odobenus rosmarus) is a large flippered Marine mammal with a discontinuous circumpolar distribution in the Arctic Ocean and Otariids are adapted to a semi-aquatic 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. The Pacific Ocean is the largest of the Earth 's Oceanic divisions The Southern Ocean, also known as the Great Southern Ocean, the Antarctic Ocean and the South Polar Ocean, comprises the southernmost waters of The Indian Ocean is the third largest of the world's Oceanic divisions covering about 20% of the water on the Earth 's surface They are conspicuously absent in the north Atlantic.

The name otariid comes from the Greek otarion meaning "little ear",[1] referring to the small but visible external ear flaps (pinnae) which can be used to distinguish them from the phocids. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly The pinna ( Latin for Feather) is the visible part of the Ear that resides outside of the head (this may also be referred to as the auricle or

Contents

Evolution and taxonomy

Along with the Phocidae and Odobenidae, the two other members of Pinnipedia, Otаriidae are descended from a common ancestor most closely related to modern bears. The walrus ( Odobenus rosmarus) is a large flippered Marine mammal with a discontinuous circumpolar distribution in the Arctic Ocean and Enaliarctos is an extinct genus of Pinniped. Five species in the genus Enaliarctos represent the oldest known pinniped fossils and have been recovered [2] There remains debate as to whether the phocids diverged from the otariids before or after the walruses.

Otariids arose in the late early Miocene (20–15 million years ago) in the North Pacific, diversifying rapidly into the Southern Hemisphere where most species now live. The Miocene is a geological epoch of the Neogene period and extends from about 23 The Callorhinus (northern fur seal) genus is considered to have the oldest lineage. The Northern Fur Seal, Callorhinus ursinus, is an Eared seal found along the north Pacific Ocean, the Bering Sea and the Sea of Okhotsk

Traditionally, otariids had been subdivided into the fur seal (Arctocephalinae) and sea lion (Otariinae) subfamilies, with the major distinction between them being the presence of a thick underfur layer in the former. Under this categorization, the fur seals comprised two genera: Callorhinus in the North Pacific with a single representative, the northern fur seal (C. The Northern Fur Seal, Callorhinus ursinus, is an Eared seal found along the north Pacific Ocean, the Bering Sea and the Sea of Okhotsk ursinus) and eight species in the southern hemisphere under the genus Arctocephalus, while the sea lions comprise five species under five genera. [3] Recent analyses of the genetic evidence suggests that the Callorhinus ursinus is in fact more closely related to several sea lion species. [4] Furthermore, many of the Otariinae appear to be more phylogenetically distinct than previously assumed; for example, the Zalophus japonicus is now considered a separate species, rather than a subspecies of Zalophus californius. Japanese Sea Lion ( Zalophus japonicus) is thought to have become Extinct in the 1950s The California Sea Lion ( Zalophus californianus) is a coastal Sea lion of the northern Pacific Ocean. In light of this evidence, the subfamily separation has been removed entirely and the Otariidae family has been organized into seven genera with 16 species and two subspecies. [5][6]

Nonetheless, because of morphological and behavioral similarity among the "fur seals" and "sea lions", these remain useful categories when discussing differences between groups of species.

Anatomy and Appearance

Otariids have proportionately much larger foreflippers and pectoral muscles than phocids, and have the ability to turn their hind limbs forward and walk on all fours, making them far more maneuverable on land. They are generally considered to be less adapted to an aquatic lifestyle, since they breed primarily on land and haul out more frequently than true seals. However, they can attain higher bursts of speed and greater maneuverability in the water. Their swimming power derives from the use of flippers more so than the sinuous whole body movements typical of phocids and walruses.

Otariids are further distinguished by a more dog-like head, sharp, well-developed canines and the aforementioned visible external pinnae. Their postcanine teeth are generally simple and conical in shape. The dental formula for eared seals is:

3. Dentition is the development of Teeth and their arrangement in the Mouth. 1. 4. 1-3
2. 1. 4. 1

Sea lions are covered with coarse guard hairs, while fur seals have a thick underfur which have historically made them the objects of commercial exploitation. Sealing redirects here for other uses see Sealing (disambiguation.

Male otariids range in size from the 70 kg (150 lbs) Galapagos fur seal, smallest of all pinnipeds, to the over 1000 kg (2200 lbs) Steller sea lions. The Galapagos Fur Seal ( Arctocephalus galapagoensis) breeds on the Galapagos Islands in the eastern Pacific west of Ecuador. The Steller sea lion, Eumetopias jubatus, also known as the northern sea lion, is a Sea lion of the northern Pacific. Mature male otariids weigh two to six times more than females with proportionately larger heads, necks, and chests, making them the most sexually dimorphic of all mammals. Sexual dimorphism is the systematic difference in form between individuals of different Sex in the same Species. [7]

Behavior

All otariids breed on land during well-defined breeding seasons. Except for the Australian sea lion, which has an atypical 17. The Australian Sea Lion ( Neophoca cinerea) is a species of Sea lion that breeds only on the south and west coasts of Australia. 5 month breeding cycle, they form strictly annual aggregations on beaches or rocky substrates, often on islands. All species are polygynous, i. Polygyny (which comes from neo- Greek: πολύ poly "many" + γυνή gyny "woman" is a specific form of Polygamy, e. successful males breed with several females. In most species, males arrive at breeding sites first and establish and maintain territories through vocal and visual displays and occasional fighting. Females typically arrive on shore a day or so before giving birth. While considered social animals, there are no permanent hierarchies or statuses established on the colonies. The extent to which males control females or territories varies between species. Thus northern fur seals and South American sea lions tend to herd specific harem-associated females, occasionally injuring them, while Steller sea lions and New Zealand sea lions control spatial territories but do not generally interfere with the movement of the females. Otaria redirects here If you are looking for the continent in Magic The Gathering, see Otaria. The New Zealand Sea Lion ( Phocarctos hookeri) also known as Hooker's Sea Lion or Whakahao in Māori is a species of Sea lion

Otariids are carnivorous, feeding on fish, squid and krill. Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two Squid are marine Cephalopods of the order Teuthida, which comprises around 300 species Krill are a type of Shrimp -like marine Invertebrate animal These small Crustaceans are important organisms of the Zooplankton, particularly Sea lions tend to feed closer to shore in upwelling zones feeding on larger fish while the smaller fur seals tend to take longer, offshore foraging trips and can subsist on large numbers of smaller prey items. Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense cooler and usually nutrient-rich water towards the ocean surface replacing the warmer They are visual feeders and some females are capable of dives up to 400 m (1300 ft).

Species

Notes

  1. ^ “Otary, n. The true seals or earless seals are one of the three main groups of Mammals within the seal Suborder, Pinnipedia. The walrus ( Odobenus rosmarus) is a large flippered Marine mammal with a discontinuous circumpolar distribution in the Arctic Ocean and , etymology of” The Oxford English Dictionary. 2nd ed. 1989. OED Online. Oxford University Press. http://dictionary.oed.com/ Accessed November 2007
  2. ^ Lento, G. M. , Hickson, R. E. , Chambers, G. K. , Penny, D. (1995) Use of spectral analysis to test hypotheses on the origin of pinnipeds. Molecular Biology and Evolution 12(1) : 28-52.
  3. ^ J. E. King (1983) Seals of the World (2nd edition). Cornell University Press, New York. ISBN 978-0702216947
  4. ^ Wynen, L. P. et al. (2001) Phylogenetic relationships within the eared seals (Otariidae: Carnivora): implications for the historical biogeography of the family. Mol. Phylog. Evol. 21, 270–284
  5. ^ Brunner, S. (2003) Fur seals and sea lions (Otariidae): identification of species and taxonomic review. Systematics and Biodiversity 1(3):339-439.
  6. ^ Scientific Name: Otariidae, Integrated Taxonomic Information System-North America - accessed November, 2007
  7. ^ Weckerly, FW (1998). "Sexual-size dimorphism: influence of mass and mating systems in the most dimorphic mammals. ". Journal of Mammalogy 79 (1): 33-42.  

Further reading

External links

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