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77-472: Elephant seals or sea elephants are very large, oceangoing earless seals in the genus Mirounga . Both species, the northern elephant seal ( M. angustirostris ) and the southern elephant seal ( M. leonina ), were hunted to the brink of extinction for oil by the end of the 19th century, but their numbers have since recovered. They can weigh up to 4,000 kilograms (8,800 lb). Despite their name, elephant seals are not closely related to elephants , and
154-675: A monophyletic origin. A 2021 genetic study found that pinnipeds are more closely related to musteloids. Pinnipeds split from other caniforms 50 million years ago ( mya ) during the Eocene . The earliest fossils of pinnipeds date back to the Late Oligocene . Fossil animals representing basal lineages include Puijila , of the Early Miocene in Arctic Canada. It resembled a modern otter, but shows evidence of quadrupedal swimming—retaining
231-616: A monophyletic group (descended from one ancestor). Pinnipeds belong to the suborder Caniformia of 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 1 m (3 ft 3 in) and 45 kg (100 lb) Baikal seal to the 5 m (16 ft) and 3,200 kg (7,100 lb) southern elephant seal . Several species exhibit sexual dimorphism . They have streamlined bodies and four limbs that are modified into flippers . Though not as fast in
308-527: A bit deeper due to their prey source. Elephant seals are shielded from extreme cold more by their blubber than by fur. Their hair and outer layers of skin molt in large patches. The skin has to be regrown by blood vessels reaching through the blubber. When molting occurs, the seal is susceptible to the cold, and must rest on land, in a safe place called a " haul out ". Northern males and young adults haul out during June to July to molt; northern females and immature seals during April to May. Elephant seals have
385-615: A few, such as the leopard seal , feed on large vertebrates, such as penguins and other seals. Walruses are specialized for feeding on bottom-dwelling mollusks . Male pinnipeds typically mate with more than one female ( polygyny ), though the degree of polygyny varies with the species. The males of land-breeding species tend to mate with a greater number of females than those of ice breeding species . Male pinniped strategies for reproductive success vary between defending females, defending territories that attract females and performing ritual displays or lek mating . Pups are typically born in
462-502: A form of aquatic locomotion that led to those employed by modern pinnipeds. Potamotherium , which lived in the same period in Europe, was similar to Puijila but more aquatic. The braincase of Potamotherium shows evidence that it used its whiskers to hunt, like modern seals. Both Puijila and Potamotherium fossils have been found in lake deposits, suggesting that seal ancestors were originally adapted for fresh water. Enaliarctos ,
539-419: A fossil species of late Oligocene /early Miocene (24–22 mya) California , closely resembled modern pinnipeds; it was adapted to an aquatic life with flippers and a flexible spine. Its teeth were more like land predators in that they were more adapted for shearing . Its hind-flippers may have allowed it to walk on land, and it probably did not leave coastal areas as much as its modern relatives. Enaliarctos
616-581: A layer of fat, or blubber , under the skin to keep warm in cold water, and, other than the walrus, all species are covered in fur. Although pinnipeds are widespread, most species prefer the colder waters of the Northern and Southern Hemispheres. They spend most of their lives in water, but come ashore to mate, give birth, molt or to avoid ocean predators, such as sharks and orcas . Seals mainly live in marine environments but can also be found in fresh water. They feed largely on fish and marine invertebrates ;
693-402: A little less than 20 minutes at the time while sinking through the water to depths that has been measured to 377 meters. When being near the continental shelf, where the ocean is less deep, they will often reach bottom, which sometimes wakes them up. But more often they continue to sleep on the seabed. On average, they get about two hours of sleep a day over a period of seven months, which is among
770-628: A long time underwater between breaths. Air is forced from the lungs during a dive and into the upper respiratory passages, where gases cannot easily be absorbed into the bloodstream. This helps protect the seal from the bends . The middle ear is also lined with blood sinuses that inflate during diving, helping to maintain a constant pressure. Phocids are more specialized for aquatic life than otariids. They lack external ears and have sleek, streamlined bodies. Retractable nipples , internal testicles , and an internal penile sheath provide further streamlining. A smooth layer of blubber lies underneath
847-519: A member of the tribe Miroungini described from the late Pliocene Petane Formation of New Zealand. Teeth originally identified as representing an unnamed species of Mirounga have been found in South Africa, and dated to the Miocene epoch; however, Boessenecker and Churchill (2016) considered these teeth almost certainly to be misidentified toothed whale (odontocete) teeth. The elephant seals evolved in
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#1733094261192924-505: A monophyletic origin for all pinnipeds from a single ancestor, possibly Enaliarctos , most closely related to the mustelids and bears . Monk seals and elephant seals were previously believed to have first entered the Pacific through the open straits between North and South America, with the Antarctic true seals either using the same route or travelled down the west coast of Africa. It
1001-509: A month to complete. When it comes time to molt, they will haul out on land to shed their outer layer, and will not consume any food during this time. The females and juveniles will molt first, followed by the sub adult males, and finally the large mature males. The main predators of elephant seals are killer whales and great white sharks . Cookiecutter sharks can take bites from their skin. Sheathbills , Skuas , Western Gulls , and African feral cats have been reported to steal milk from
1078-439: A short period. This allows the mother to return to the sea in time to replenish her reserves. Lactation ranges from five to seven weeks in the monk seal to just three to five days in the hooded seal . The mother ends nursing by leaving her pup at the breeding site to search for food (pups continue to nurse if given the opportunity). "Milk stealers" that suckle from unrelated, sleeping females are not uncommon; this often results in
1155-404: A structure called the tapetum lucidum , which helps their vision by having light reflected back to the retina to allow more chances for photoreceptors to detect light. Their body is covered in blubber, which helps them keep warm and reduce drag while they are swimming. The shape of their body also helps them maneuver well in the water, but limits their movement on land. Also, elephant seals have
1232-473: A third of their body weight during the breeding season. The gestation period for females is 11 months, and the pupping seasons lasts from mid to late summer. The new pups will spend up to 10 additional weeks on land learning how to swim and dive. The average lifespan of a northern elephant seal is 9 years, while the average lifespan of a southern elephant seal is 21 years. Males reach maturity at five to six years, but generally do not achieve alpha status until
1309-582: A very large volume of blood, allowing them to hold a large amount of oxygen for use when diving. They have large sinuses in their abdomens to hold blood and can also store oxygen in their muscles with increased myoglobin concentrations in muscle. In addition, they have a larger proportion of oxygen-carrying red blood cells . These adaptations allow elephant seals to dive to such depths and remain underwater for up to two hours. Unlike some other marine mammals, such as dolphins, elephant seals do not have unihemispheric slow-wave sleep . Instead they sleep deeply for
1386-541: A way to maintain a constant body temperature by having the cool blood flowing to the heart warmed by blood going to external areas of the animal. Milk produced by elephant seals is remarkably high in milkfat compared to other mammals. After an initially lower state, it rises to over 50% milkfat (human breast milk is about 4% milkfat, and cow milk is about 3.5% milkfat). Elephant seals have large circular eyes that have more rods than cones to help them see in low light conditions when they are diving. These seals also possess
1463-553: A weight of 3,000 kg (7,000 lb), and are much larger than the adult females (cows), with some exceptionally large males reaching up to 6 m (20 ft) in length and weighing 4,000 kg (9,000 lb); cows typically measure about 3 m (10 ft) and 900 kg (2,000 lb). Northern elephant seal bulls reach a length of 4.3 to 4.8 m (14 to 16 ft) and the heaviest weigh about 2,500 kg (5,500 lb). The northern and southern elephant seal can be distinguished by various external features. On average,
1540-520: 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), with 34 extant species and more than 50 extinct species described from fossils . While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as
1617-460: 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 European freshwater lakes. Recent evidence strongly suggests
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#17330942611921694-669: Is 0.83 for experienced breeding females, but only 0.66 for first-time breeders indicating a significant cost of reproduction. More male pups are produced than female pups in years with warmer sea surface temperature in the northeastern Pacific Ocean. Females and males utilize different feeding strategies in order to maximize their reproductive success. Males feed in benthic regions with more abundant food sources, but also more abundant predators. Females feed in pelagic regions where they are less likely to find prey, but also less likely to be preyed upon. They employ these different strategies because females are smaller, requiring less food, and it
1771-422: Is about 300 to 600 m (1,000 to 2,000 ft), typically for around 20 minutes for females and 60 minutes for males, as they search for their favorite foods, which are skates , rays , squid , octopuses , eels , small sharks and large fish. Their stomachs also often contain gastroliths . They spend only brief amounts of time at the surface to rest between dives (2–3 minutes). Females tend to dive
1848-512: Is aided by a specialized skull, mandible, and tooth morphology. However, despite morphological specialization, most phocids are opportunistic and employ multiple strategies to capture and eat prey. For example, the leopard seal, Hydrurga leptonyx , uses grip and tear feeding to prey on penguins, suction feeding to consume small fish, and filter feeding to catch krill. [REDACTED] Pinniped Pinnipeds (pronounced / ˈ p ɪ n ɪ ˌ p ɛ d z / ), commonly known as seals , are
1925-444: Is also most important for them to have as many breeding seasons as possible in order to maximize reproductive success. On the other hand, males can adopt a riskier strategy in the hopes of gaining as much mass as possible, and thus being able to have one extremely successful breeding season. Once a year, elephant seals go through a process called molting where they shed the outer layer of hair and skin. This molting process takes up to
2002-402: Is because of their massive ankle bones and flatter heels. In water, true seals rely on the side-to-side motion of their hind-flippers and lower body to move forward. The phocid's skull has thickened mastoids , puffed up entotympanic bones , nasal bones with a pointed tip in the back and a non-existent supraorbital foramen. The hip has a more converse ilium . A 2006 molecular study supports
2079-433: Is extreme, with male elephant seals weighing up to 10 times more than females, and having a prominent proboscis . Elephant seals take their name from the large proboscis of the adult male (bull), reminiscent of an elephant's trunk, and considered a secondary sexual characteristic. The bull's proboscis is used in producing extraordinarily loud roaring noises, especially during the mating season. More importantly, however,
2156-645: Is found in the Southern Hemisphere on islands such as South Georgia and Macquarie Island , and on the coasts of New Zealand, Tasmania, South Africa, and Argentina in the Peninsula Valdés . In southern Chile, there is a small colony of 120 animals at Jackson Bay ( Bahía Jackson ) in Admiralty Sound ( Seno Almirantazgo ) on the southern coast of Isla Grande de Tierra del Fuego . The oldest known unambiguous elephant seal fossils are fragmentary fossils of
2233-616: Is now thought that the monk seals , elephant seals , and Antarctic seals all evolved in the southern hemisphere, and likely dispersed to their current distributions from more southern latitudes. Bearded seal Hooded seal Ringed seal Baikal seal Caspian seal Spotted seal Harbor seal Grey seal Ribbon seal Harp seal Weddell seal Leopard seal Crabeater seal Ross seal Southern elephant seal Northern elephant seal Mediterranean monk seal Hawaiian monk seal Caribbean monk seal Otariidae ( eared seals ) Odobenidae ( Walrus ) In
2310-486: Is protected in most countries where it lives. In Mexico, the northern elephant seal is protected in the Guadalupe Island Biosphere Reserve where it was rediscovered after being believed to be extinct. [REDACTED] 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
2387-720: The Caribbean monk seal have become extinct in the past century, while the Mediterranean monk seal and Hawaiian monk seal are ranked as endangered by the International Union for Conservation of Nature . Besides hunting, pinnipeds also face threats from accidental trapping , marine pollution , climate change and conflicts with local people. The name "pinniped" derives from the Latin words pinna ' fin ' and pes, pedis ' foot ' . The common name "seal" originates from
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2464-977: The Old English word seolh , which is in turn derived from the Proto-Germanic * selkhaz . Bearded seal Hooded seal Ringed seal Baikal seal Caspian seal Spotted seal Harbor seal Grey seal Ribbon seal Harp seal Weddell seal Leopard seal Crabeater seal Ross seal Southern elephant seal Northern elephant seal Mediterranean monk seal Hawaiian monk seal Northern fur seal Steller sea lion California sea lion Galápagos sea lion South American sea lion Australian sea lion New Zealand sea lion Brown fur seal Subantarctic fur seal Antarctic fur seal Guadalupe fur seal Juan Fernández fur seal Antipodean fur seal Galápagos fur seal South American fur seal Walrus The German naturalist Johann Karl Wilhelm Illiger
2541-501: The elephant seals ' teats. The IUCN lists both species of elephant seal as being of least concern , although they are still threatened by entanglement in marine debris , fishery interactions, and boat collisions. Though a complete population count of elephant seals is not possible because all age classes are not ashore at the same time, a 2005 study of the California breeding stock estimated approximately 124,000 individuals. The animal
2618-662: The nasal bones , with a large and flattened supraorbital foramen . An extra spine splits the supraspinatous fossa and bronchi that are divided in the front. Otariids consist of two types: sea lions and fur seals ; the latter typically being smaller, with pointier snouts, longer fore-flippers and heavier fur coats . Five genera and seven species (one now extinct) of sea lion are known to exist, while two genera and nine species of fur seal exist. While sea lions and fur seals have historically been considered separate subfamilies (Otariinae and Arctocephalinae respectively), genetic and molecular evidence has refuted this, indicating that
2695-544: The northern fur seal is basal to other otariids and the Australian sea lion and New Zealand sea lion are more closely related to Arctocephalus than to other sea lions. Odobenidae has only one living member: the walrus . This animal is noticeable from its larger size (exceeded only by the elephant seals ), nearly hairless skin, flattened snout and long upper canines , known as tusks . Like otariids, walruses can walk on land with their hind limbs. When moving in water,
2772-544: The orbital wall . The extinct family Desmatophocidae lived 23–10 mya in the North Pacific. They had long skulls that with large orbits, interlocked zygomatic bones and rounded molars and premolars . They also were sexually dimorphic and may have been capable of swimming with both or either pair of flippers. They are grouped with modern pinnipeds, but there is debate as to whether they are more closely related to phocids or to otariids and walruses. The ancestors of
2849-444: The otariids . In addition, the hind flippers of elephant seals have a lot of surface area, which helps propel them in the water. Elephant seals spend the majority of their life (90%) underwater in search of food, and can cover 100 kilometres (60 miles) a day when they head out to sea. When elephant seals are born, they can weigh up to 36 kilograms (79 pounds) and reach lengths up to 122 cm (4 ft 0 in). Sexual dimorphism
2926-480: The pelvis in such a way that they cannot bring them under their bodies to walk on them. They are more streamlined than fur seals and sea lions, so they can swim more effectively over long distances. However, because they cannot turn their hind flippers downward, they are very clumsy on land, having to wriggle with their front flippers and abdominal muscles . Phocid respiratory and circulatory systems are adapted to allow diving to considerable depths, and they can spend
3003-459: The tribe Lobodontini . Tribe Miroungini is composed of the elephant seals . The Monk seals ( Monachus and Neomonachus ) are all part of the tribe Monachini. Likewise, subfamily Phocinae (the "northern" seals) also includes three tribes; Erignathini ( Erignathus ) , Cystophorini ( Cystophora) , and Phocini (all other phocines). More recently, five species have been split off from Phoca , forming three additional genera. Alternatively
3080-485: The 1 m (3 ft 3 in) and 45 kg (100 lb) Baikal seal to the 5 m (16 ft) and 3,200 kg (7,100 lb) southern elephant seal . Overall, they tend to be larger than other carnivores. Several species have male-biased sexual dimorphism that depends on how polygynous a species is: highly polygynous species like elephant seals are extremely sexually dimorphic, while less polygynous species have males and females that are closer in size, or, in
3157-565: The 1980s and 1990s, morphological phylogenetic analysis of the phocids led to new conclusions about the interrelatedness of the various genera. More recent molecular phylogenetic analyses have confirmed the monophyly of the two phocid subfamilies ( Phocinae and Monachinae). The Monachinae (known as the "southern" seals), is composed of three tribes; the Lobodontini, Miroungini, and Monachini. The four Antarctic genera Hydrurga , Leptonychotes , Lobodon , and Ommatophoca are part of
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3234-629: The North Atlantic, and likely reached the Pacific via the Central American Seaway . Phocines mainly stayed in the Northern Hemisphere, while the monachines diversified southward. The lineages of Otariidae and Odobenidae split around 20 mya. The earliest fossil records of otariids are in North Pacific and dated to around 11 mya. Early fossil genera include Pithanotaria and Thalassoleon . The Callorhinus lineage split
3311-531: The Otarioidea and Phocidea diverged around 25 mya. Phocids are known to have existed for at least 15 million years, and molecular evidence supports a divergence of the Monachinae and Phocinae lineages around this time. The fossil genera Monotherium and Leptophoca of southeastern North America represent the earliest members of Monachinae and Phocinae respectively. Both lineages may have originated in
3388-587: The Pacific Ocean during the Pliocene period. Elephant seals breed annually and are seemingly habitual to colonies that have established breeding areas. John Edward Gray established the genus Mirounga in 1827. The generic name Mirounga is a Latinization of miouroung , which is said to have been a term for the seal in an Australian Aboriginal language . However, it is not known which language this represents. Elephant seals are marine mammals classified under
3465-633: The ability to fast for long periods of time while breeding or molting. The turbinate process, another unique adaptation , is very beneficial when these seals are fasting, breeding, molting, or hauling out. This unique nasal structure recycles moisture when they breathe and helps prevent water loss. Elephant seals have external whiskers called vibrissae to help them locate prey and navigate their environment. The vibrissae are connected to blood vessels, nerves, and muscles making them an important sensing tool. Due to evolutionary changes, their ear has been modified to work extremely well underwater. The structure of
3542-409: The age of eight, with the prime breeding years being between ages 9 and 12. The longest life expectancy of a male northern elephant seal is approximately 14 years. Females begin breeding at age 3–6, and have one pup per breeding attempt. Most adult females breed each year. Breeding success is much lower for first-time mothers relative to experienced breeders. Annual survival probability of adult females
3619-455: The body. Seals are unique among carnivorans in that their orbital walls are mostly shaped by the maxilla and are not contained by certain facial bones. Compared to land carnivores, pinnipeds have fewer teeth, which are pointed and cone-shaped. They are adapted for holding onto slippery prey rather than shearing meat like the carnassials of other carnivorans. The walrus has unique tusks which are long upper canines. Pinnipeds range in size from
3696-411: The breeding site to use their stored energy to nurse pups. 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. Because a phocid mother's feeding grounds are often hundreds of kilometers from the breeding site, she must fast while lactating . This combination of fasting with lactation requires
3773-399: The case of Antarctic seals, females are moderately bigger. Males of sexually dimorphic species also tend to have secondary sex characteristics , such as larger or more prominent heads, necks, chests, crests , noses/ proboscises and canine teeth as well as thicker fur and manes. Though more polygynous species tend to be sexually dimorphic, some evidence suggests that size differences between
3850-494: The complex songs of Weddell seals . The meat, blubber and skin of pinnipeds have traditionally been used by indigenous peoples of the Arctic . Seals have been depicted in various cultures worldwide. They are commonly kept in captivity and are even sometimes trained to perform tricks and tasks. Once relentlessly hunted by commercial industries for their products, seals are now protected by international law. The Japanese sea lion and
3927-489: The death of the mother's pup, since a female can only feed one pup. The pup's diet is so high in calories that it builds up a fat store. Before the pup is ready to forage, the mother abandons it, and the pup consumes its own fat for weeks or even months while it matures. Seals, like all marine mammals, need time to develop the oxygen stores, swimming muscles, and neural pathways necessary for effective diving and foraging. Seal pups typically eat no food and drink no water during
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#17330942611924004-467: The division of phocids into two monophyletic subfamilies: Monachinae, which consists of elephant seals, monk seals and Antarctic seals ; and Phocinae, which consists of all the rest. One popular hypothesis suggested that pinnipeds are diphyletic (descended from two ancestral lines), with walruses and otariids sharing a recent common ancestor with bears ; and phocids sharing one with Musteloidea . However, morphological and molecular evidence support
4081-401: The dominant males. By the time males reach eight to nine years of age, they have developed a pronounced long nose, in addition to a chest shield, which is thickened skin in their chest area. They display their dominance by showing their noses, making loud vocalisations, and altering their postures. They fight each other by raising themselves and ramming each other with their chests and teeth. By
4158-535: The earliest, followed by the Eumetopias / Zalophus lineage and then the rest, which colonized the Southern Hemisphere. The earliest fossils of Odobenidae— Prototaria of Japan and Proneotherium of Oregon—date to 18–16 mya. These primitive walruses had normal sized canines and fed on fish instead of mollusks. Later taxa like Gomphotaria , Pontolis and Dusignathus had longer canines on both
4235-473: The family Phocidae ( / ˈ f oʊ s ɪ d iː / ). 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 . The earliest known fossil earless seal
4312-406: The females while the alpha is occupied. Birth on average only takes a few minutes, and the mother and pup have a connection due to each other's unique smell and sound. The mothers will fast and nurse up to 28 days, providing their pups with rich milk. The last two to three days, however, females will be ready to mate, and the dominant males will pounce on the opportunity. Males and females lose up to
4389-499: The inner ear helps amplify incoming sounds, and allows these seals to have good directional hearing due to the isolation of the inner ear. In addition to these adaptations, tissues in the ear canal allow the pressure in the ear to be adjusted while these seals perform their deep dives. Males arrive at potential breeding sites in spring, and fast to ensure that they can mate with as many females as possible. Male elephant seals use fighting, vocalisations, and different positions to determine
4466-569: The large proboscis or trunk that males have was convergently evolved . The northern elephant seal, somewhat smaller than its southern relative, ranges over the Pacific coast of the U.S., Canada and Mexico. The most northerly breeding location on the Pacific Coast is at Race Rocks Marine Protected Area , at the southern tip of Vancouver Island in the Strait of Juan de Fuca . The southern elephant seal
4543-460: The lowest amount of sleep of any mammal. They are able to slow down their heartbeat ( bradycardia ) and divert blood flow from the external areas of the body to important core organs. They can also slow down their metabolism while performing deep dives. Elephant seals have a helpful feature in their bodies known as the countercurrent heat exchanger to help conserve energy and prevent heat loss. In this system, arteries and veins are organized in
4620-480: The mother to provide large amounts of energy to her pup at a time when she is not eating (and often, not drinking). Mothers must supply their own metabolic needs while nursing. 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. Phocids produce thick, fat-rich milk that allows them to provide their pups with large amounts of energy in
4697-415: The nose acts as a sort of rebreather , filled with cavities that reabsorb moisture from their exhalations. This is important during the mating season when the seals do not leave the beach to feed, and must conserve body moisture as there is no incoming source of water. They are very much larger than other pinnipeds , with southern elephant seal bulls typically reaching a length of 5 m (16 ft) and
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#17330942611924774-412: The ocean. They can hold their breath for more than 100 minutes – longer than any other noncetacean mammal. Elephant seals dive to 1,550 m (5,090 ft) beneath the ocean's surface (the deepest recorded dive of an elephant seal is 2,388 m (7,835 ft) by a southern elephant seal, while the record for the northern elephant seal is 1,735 m (5,692 ft)). The average depth of their dives
4851-728: The order Carnivora . Phocids have fewer teeth than land-based members of the Carnivora , although they retain powerful canines . Some species lack molars altogether. The dental formula is: 2–3.1.4.0–2 1–2.1.4.0–2 While otariids are known for speed and maneuverability, phocids are known for efficient, economical movement. This allows most phocids to forage far from land to exploit prey resources, while otariids are tied to rich upwelling zones close to breeding sites. Phocids swim by sideways movements of their bodies, using their hind flippers to fullest effect. Their fore flippers are used primarily for steering, while their hind flippers are bound to
4928-488: The order Pinnipedia, which, in Latin, means feather- or fin-footed. Elephant seals are considered true seals, and fall under the family Phocidae. Phocids (true seals) are characterized by having no external ear and reduced limbs. The reduction of their limbs helps them be more streamlined and move easily in the water. However, it makes navigating on land more difficult because they cannot turn their hind flippers forward to walk like
5005-523: The period, although some polar species eat snow. The postweaning fast ranges from two weeks in the hooded seal to 9–12 weeks in the northern elephant seal. 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. Phocids make use of at least four different feeding strategies: suction feeding, grip and tear feeding, filter feeding, and pierce feeding. Each of these feeding strategies
5082-432: The skin. Phocids are able to divert blood flow to this layer to help control their temperatures. Unlike otariids, true seals do not communicate by 'barking'. Instead, they communicate by slapping the water and grunting. Phocids spend most of their time at sea, although they return to land or pack ice to breed and give birth. Pregnant females spend long periods foraging at sea, building up fat reserves, and then return to
5159-556: The southern elephant seal tends to be larger than the northern species. Adult male elephant seals belonging to the northern species tend to have a larger proboscis, and thick chest area with a red coloration compared to the southern species. Females do not have the large proboscis and can be distinguished between species by looking at their nose characteristics. Southern females tend to have a smaller, blunt nose compared to northern females. [REDACTED] [REDACTED] Elephant seals spend up to 80% of their lives in
5236-429: The spring and summer months and females bear almost all the responsibility for raising them. Mothers of some species fast and nurse their young for a relatively short period of time while others take foraging trips at sea between nursing bouts. Walruses are known to nurse their young while at sea. Seals produce a number of vocalizations , notably the barks of California sea lions , the gong -like calls of walruses and
5313-406: The superfamily Phocoidea. There are 34 extant species of pinnipeds, and more than 50 fossil species of pinnipedimorphs. Otariids are also known as eared seals due to their pinnae . These animals swim mainly using their well-developed fore-flippers. They can also "walk" on land by shifting their hind-flippers forward under the body. The front end of an otariid's frontal bone protrudes between
5390-400: The three monachine tribes have been evaluated to familiar status, which elephant seals and the Antarctic seals are more closely related to the phocines. Adult phocids vary from 1.17 m (3.8 ft) in length and 45 kg (99 lb) in weight in the ringed seal to 5.8 m (19 ft) and 4,000 kg (8,800 lb) in the southern elephant seal , which is the largest member of
5467-428: The time females arrive, each dominating male has already established his territory on the beach. Females cluster in groups called harems, which consist of up to 50 females surrounding one alpha male. Outside of these groups, a beta bull is normally roaming around on the beach. The beta bull helps the alpha by preventing other males accessing the females. In return, the beta bull might have an opportunity to mate with one of
5544-751: The upper and lower jaw. The familiar long upper tusks developed in the genera Valenictus and Odobenus . The lineage of the modern walrus may have spread from the North Pacific to the North Atlantic through the Caribbean and Central American Seaway 8–5 mya, and then back to the North Pacific via the Arctic 1 mya, or to the Arctic and subsequently the North Atlantic during the Pleistocene . Pinnipeds have streamlined, spindle-shaped bodies with small or non-existent ear flaps, rounded heads, short muzzles, flexible necks, limbs modified into flippers and small tails. The mammary glands and genitals can withdraw into
5621-445: The walrus relies on its hind limbs for locomotion, while its forelimbs are used for steering. Also, it has no outer ears. The epipterygoid of the jaw is well developed and the back of the nasal bones are horizontal. In the feet, the calcaneuses protrude in the middle. Phocids are known as true or "earless" seals. These animals lack outer ears and cannot position their hind-flippers to move on land, making them more cumbersome. This
5698-704: The water as dolphins , seals are more flexible and agile. Otariids primarily use their front limbs to propel themselves through the water, while phocids and walruses primarily use their hind limbs for this purpose. Otariids and walruses have hind limbs that can be pulled under the body and used as legs on land. By comparison, terrestrial locomotion by phocids is more cumbersome. Otariids have visible external ears, while phocids and walruses lack these. 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. Some species are well adapted for diving to great depths. They have
5775-524: The world. In 1989, Annalisa Berta and colleagues proposed the unranked clade Pinnipedimorpha to contain the fossil genus Enaliarctos and modern seals as a sister group . Pinnipeds belong to the order Carnivora and the suborder Caniformia (known as dog-like carnivorans). Of the three extant families, the Otariidae and Odobenidae are grouped in the superfamily Otarioidea, while the Phocidae belong to
5852-491: Was likely more of a fore-flipper swimmer, but could probably swim with either pair. One species, Enaliarctos emlongi , exhibited notable sexual dimorphism , suggesting that this physical characteristic may have been an important driver of pinniped evolution. A closer relative of extant pinnipeds was Pteronarctos , which lived in Oregon 19–15 mya. As in modern seals, the maxilla or upper jaw bone of Pteroarctos intersects with
5929-527: Was the first to recognize the pinnipeds as a distinct taxonomic unit; in 1811 he gave the name Pinnipedia to both a family and an order . American zoologist Joel Asaph Allen reviewed the world's pinnipeds in an 1880 monograph , History of North American pinnipeds, a monograph of the walruses, sea-lions, sea-bears and seals of North America . In this publication, he traced the history of names, gave keys to families and genera, described North American species and provided synopses of species in other parts of
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