Seals live in the oceans of both hemispheres and, with the exception of the more tropical monk seals, are … 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). Sea lions (left) are brown, bark loudly, "walk" on land using their large flippers and have visible ear flaps. [12][13] Instead, they suggest three clades within the family; one consisting of the northern sea lions (Eumetopias and Zalophus), one of the northern fur seal (Callorhinus) and its extinct relatives, and the third of all the remaining Southern Hemisphere species.[14]. Nonetheless, because of morphological and behavioral similarities among the "fur seals" and "sea lions", these remain useful categories when discussing differences between groups of species. Male otariids range in size from the 70-kg (150-lb) Galápagos fur seal, smallest of all pinnipeds, to the over 1,000-kg (2,200-lb) Steller sea lion. Otariids are carnivorous, feeding on fish, squid and krill. Seal pups typically eat no food and drink no water during the period, although some polar species eat snow.

Although the two subfamilies of otariids, the Otariinae (sea lions) and Arctocephalinae (fur seals), are still widely used, recent molecular studies have demonstrated that they may be invalid. [18], Learn how and when to remove this template message, "A critical revision of the fossil record, stratigraphy and diversity of the Neogene seal genus, "On Prophoca and Leptophoca (Pinnipedia, Phocidae) from the Miocene of the North Atlantic realm: redescription, phylogenetic affinities and paleobiogeographic implications", "A Total Evidence Phylogenetic Analysis of Pinniped Phylogeny and the Possibility of Parallel Evolution Within a Monophyletic Framework", "Multiple markers and multiple individuals refine true seal phylogeny and bring molecules and morphology back in line", "Biogeography and taxonomy of extinct and endangered monk seals illuminated by ancient DNA and skull morphology", "The better to eat you with: the comparative feeding morphology of phocid seals (Pinnipedia, Phocidae)", https://en.wikipedia.org/w/index.php?title=Earless_seal&oldid=982891280, Articles with unsourced statements from March 2020, Articles needing additional references from July 2017, All articles needing additional references, Articles needing additional references from May 2013, Creative Commons Attribution-ShareAlike License, This page was last edited on 11 October 2020, at 00:39. An eared seal or otariid or otary is any member of the marine mammal family Otariidae, one of three groupings of pinnipeds. [5] Recent analyses of the genetic evidence suggests that Callorhinus ursinus is in fact more closely related to several sea lion species. They reside in subpolar, temperate, and equatorial waters throughout the Pacific and Southern Oceans and the southern Indian and Atlantic Oceans. As true seals -- family Phocidae members -- harp seals do not have pinnae, which are the protruding segments of ears. [14] Their fore flippers are used primarily for steering, while their hind flippers are bound to the pelvis in such a way that they cannot bring them under their bodies to walk on them.
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. All true seals are members of the family Phocidae /ˈfoʊsɪdiː/. Compared to sea lions, fur seals are generally smaller, exhibit greater sexual dimorphism, eat smaller prey and go on longer foraging trips; and, of course, there is the contrast between the coarse short sea lion hair and the fur seal's fur. Seals are quieter, vocalizing via soft grunts. †Thalassoleon This is a miniature version of the humpback whales' strategy, which involves fasting during their months-long migration from arctic feeding areas to tropical breeding/nursing areas and back. The extent to which males control females or territories varies between species. This allows the mother to return to the sea in time to replenish her reserves. Sea lions (left) are brown, bark loudly, "walk" on land using their large flippers and have visible ear flaps. Finally, seals are less social than their sea-lion cousins. Sea lions, on the other hand, are able to "walk" on land by rotating their hind flippers forward and underneath their big bodies. However, despite morphological specialization, most phocids are opportunistic and employ multiple strategies to capture and eat prey. Sea lions are covered with coarse guard hairs, while fur seals have a thick underfur, which has historically made them the objects of commercial exploitation. The middle ear is also lined with blood sinuses that inflate during diving, helping to maintain a constant pressure. Secondly, sea lions have small flaps for outer ears. Oxford University Press. They lack external ears and have sleek, streamlined bodies. [10] Likewise, subfamily Phocinae (the "northern" seals) also includes three tribes; Erignathini (Erignathus), Cystophorini (Cystophora), and Phocini (all other phocines). However, the common seal displays a reproductive strategy similar to that used by otariids, in which the mother makes short foraging trips between nursing bouts. 99 DOI: 10.1126/science.157.3784.99 In light of this evidence, the subfamily separation has been removed entirely and the family Otariidae has been organized into seven genera with 16 species and two subspecies. "Otary, n., etymology of" The Oxford English Dictionary. Science 07 Jul 1967: Vol. †Pithanotaria 157, Issue 3784, pp. The insides of their ears also closely resemble those of many of their fellow mammals. All otariids breed on land during well-defined breeding seasons.

Because a phocid mother's feeding grounds are often hundreds of kilometers from the breeding site, she must fast while lactating. Both seals and sea lions, together with the walrus, are pinnipeds, which means "fin footed" in Latin. "Milk stealers" that suckle from unrelated, sleeping females are not uncommon; this often results in the death of the mother's pup, since a female can only feed one pup. Instead, they communicate by slapping the water and grunting. Sea lions congregate in gregarious groups called herds or rafts that can reach upwards of 1,500 individuals. Refer to the article's text about the interrelationships among the phocid subfamilies. It probably arose from the extinct fur seal genus Thalassoleon. [5] The various Antarctic species may have either used the same route, or traveled down the west coast of Africa. †Eotaria Otariids are adapted to a semiaquatic lifestyle, feeding and migrating in the water, but breeding and resting on land or ice. Author: NOAA Except for the Australian sea lion, which has an atypical 17.5 month breeding cycle, they form strictly annual aggregations on beaches or rocky substrates, often on islands. [17] The physiological and behavioral adaptations that allow phocid pups to endure these remarkable fasts, which are among the longest for any mammal, remain an area of active study and research. Other types of seals without visible ears are harbor seals (Phoca vitulina), Hawaiian monk seals (Monachus schauinslandi) … Under this categorization, the fur seals comprised two genera: Callorhinus in the North Pacific with a single representative, the northern fur seal (C. ursinus), and eight species in the Southern Hemisphere under the genus Arctocephalus; while the sea lions comprise five species under five genera. [4] Debate remains as to whether the phocids diverged from the otariids before or after the walrus. Seals and sea lions are marine mammals called ' pinnipeds ' that differ in physical characteristics and adaptations. While considered social animals, no permanent hierarchies or statuses are established on the colonies. "Use of spectral analysis to test hypotheses on the origin of pinnipeds", "Fur seals and sea lions (Otariidae): identification of species and taxonomic review", "Sexual-size dimorphism: influence of mass and mating systems in the most dimorphic mammals", https://en.wikipedia.org/w/index.php?title=Eared_seal&oldid=982891274, Articles with Japanese-language sources (ja), Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License, Perrin, W. F., B. Würsig, and J. G. M. Thewissen (2002), This page was last edited on 11 October 2020, at 00:39.
While otariids are known for speed and maneuverability, phocids are known for efficient, economical movement. Their swimming power derives from the use of flippers more so than the sinuous whole-body movements typical of phocids and walruses. The earliest known fossil earless seal is Noriphoca gaudini from the late Oligocene or earliest Miocene (Aquitanian) of Italy. This combination of fasting with lactation requires the mother to provide large amounts of energy to her pup at a time when she is not eating (and often, not drinking). Phocid respiratory and circulatory systems are adapted to allow diving to considerable depths, and they can spend a long time underwater between breaths.

Otariids are further distinguished by a more dog-like head, sharp, well-developed canines, and the aforementioned visible external pinnae. Seals have small flippers, wriggle on their bellies on land, and lack visible ear flaps. The "earless" or "true" seals lack external ears altogether. Callorhinus [1] Other early fossil phocids date from the mid-Miocene, 15 million years ago in the north Atlantic. You have to get very close to see the tiny holes on the sides of a seal’s sleek head.