what are the 18 species of seals in order

[105], Pinnipeds lessen the chance of predation by gathering in groups. When foraging, for example, the Weddell seal typically dives for less than 15minutes to depths of around 400m (1,300ft) but can dive for as long as 73minutes and to depths of up to 600m (2,000ft). [130] For most species, birthing takes place in the spring and summer months. This animal is easily distinguished from other extant pinnipeds by its larger size (exceeded only by the elephant seals), nearly hairless skin and long upper canines, known as tusks. The vibrissa's angle relative to the flow, not the shape, however, seems to be the most important factor. The scientific name of a seal is Pinnipedia. Pinnipeds also have very muscular and vascularized irises. Seals see very well under waterbetter than they do in bright light above water. There are 18 species of true seals, according to Seals World. Like other marine mammals, seals sleep in water with half of their brain awake so that they can detect and escape from predators. These tissue masses, which contain extensive contorted spirals of arteries and thin-walled veins, act as blood reservoirs that increase oxygen stores for use during diving. [16] This is supported by a 2006 molecular study that also found that the Australian sea lion and New Zealand sea lion are more closely related to Arctocephalus than to other sea lions. Otariids use their front limbs primarily to propel themselves through the water, while phocids and walruses use their hind limbs. When threatened by other adults or when pups try to suckle, females make a harsh, pulsed call. Pups of these species are weaned at lower weights than their phocid counterparts. In the Bahamas, as many as 100 seals were slaughtered in one night. Most of the other otariids diversified in the Southern Hemisphere. [116][121] Lekking may also exist among California sea lions, South American fur seals, New Zealand sea lions and harbor seals. [151][152], Non-vocal communication is not as common in pinnipeds as in cetaceans. Older crabeater seals commonly bear scars from failed leopard seal attacks; a 1977 study found that 75% of a sample of 85 individual crabeaters had these scars. Both killer whales and sharks like to swallow their food . Seals range in size from the 1m (3ft 3in) and 45kg (99lb) Baikal seal to the 5m (16ft) and 3,200kg (7,100lb) southern elephant seal male, which is also the largest member of the order Carnivora. The northern sea lion is the largest species, with males growing up to 3 m long and weighing 900 kg. [138] Subadult male South America sea lions sometimes abduct pups from their mothers and treat them like adult males treat females. When moving in water, the walrus relies on its hind-flippers for locomotion, while its fore-flippers are used for steering. Get a Britannica Premium subscription and gain access to exclusive content. [21], Enaliarctos, a fossil species of late Oligocene/early Miocene (2422mya) California, closely resembled modern pinnipeds; it was adapted to an aquatic life with a flexible spine, and limbs modified into flippers. They state that the exhibits could not be large enough to house animals that have evolved to be migratory, and a pool could never replace the size and biodiversity of the ocean. The Baikal seal (Phoca sibirica) of Lake Baikal in Siberia, Russia, is the smallest at 1.11.4 metres (3.64.6 feet) long and 50130 kg (110290 pounds), but some female fur seals weigh less. The earliest fossil Pithanotaria, found in California, is dated to 11mya. 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 the world. Animals Reference Seals Common Name: Seals Scientific Name: Pinnipedia Diet: Carnivore Average Life Span In The Wild: Up to 30 years Size: 3 feet to 20 feet long Weight: 100 pounds to 4.4. [117][118] Males defend their territorial boundaries with threatening vocalizations and postures, but physical fights are usually avoided. This dimorphism manifests itself in larger chests and necks, longer canines and denser furall traits that help males in fights for females. Antarctic seals are more vocal on land or ice than Arctic seals due to a lack of terrestrial and pagophilic predators like the polar bear. [111], Polygynous species also tend to be extremely sexual dimorphic in favor of males. The researchers who found Puijila placed it in a clade with Potamotherium (traditionally considered a mustelid) and Enaliarctos. They spend most of their lives in the water, but come ashore to mate, give birth, molt or escape from predators, such as sharks and orcas. Seals, facts and photos - National Geographic Besides hunting, pinnipeds also face threats from accidental trapping, marine pollution, climate change and conflicts with local people. [138] Male walruses may help inexperienced young as they learn to swim, and have even been recorded caring for orphans. Polygynous species include elephant seals, grey seals and most otariids. The leopard seal is known to prey on numerous other species, especially the crabeater seal. In addition to foraging, vibrissae may also play a role in navigation; spotted seals appear to use them to detect breathing holes in the ice. [120] The maritories of Weddell seal males can overlap with female breathing holes in the ice. Seals and sea lions belong to a group of marine mammals called pinnipeds, which means fin or flipper-footed. [171], Commercial sealing was historically just as important an industry as whaling. Some species use their fore-flippers to pull themselves forward. Mouse Deer - . Proponents of seal hunts insist that the animals are killed humanely and the white-coated pups are not taken, while opponents argue that it is irresponsible to kill harp seals as they are already threatened by declining habitat. [26] Blubber serves both to keep the animals warm and to provide energy and nourishment when they are fasting. They also harass and attempt to mate with females that head out to the water. [110] Species that breed on land are usually polygynous, as females gather in large aggregations and males are able to mate with them as well as defend them from rivals. Its teeth were adapted for shearing (like terrestrial carnivorans), and it may have stayed near shore more often than its extant relatives. [38] Seals have a layer of subcutaneous fat known as blubber that is particularly thick in phocids and walruses. They can hear high pitched sounds well above the range of human hearing. They are typically hunted by groups of 10 or fewer whales, but they are occasionally hunted by larger groups or by lone individuals. It may require a year to train a sea lion to perform a trick for the public. The former also tend to be larger than the latter. Examples include the crabeater seal, which primarily eats krill, the ringed seal, which eats mainly crustaceans, the Ross seal and southern elephant seal, which specialize on squid, and the bearded seal and walrus, which feed on clams and other bottom-dwelling invertebrates. Seals mainly live in marine environments but can also be found in freshwater. The supraspinatous fossas are divided by a "secondary spine" and the bronchi are divided anteriorly. Seals and their species | Britannica [153] They demonstrate the ability to understand simple syntax and commands when taught an artificial sign language, though they only rarely used the signs semantically or logically. [115][116], Younger or subdominant male pinnipeds may attempt to achieve reproductive success in other ways. Articles from Britannica Encyclopedias for elementary and high school students. [81][82] Only monk seals live in waters that are not typically cool or rich in nutrients. [130][131] Gestation in seals (including delayed implantation) typically lasts a year. Phocids are less agile on land. [120] The underwater vocals of Weddell seals can last 70 seconds, which is long for a marine mammal call. [12], Otariids are also known as eared seals due to the presence of pinnae. All fully furred species molt; phocids molt once a year, while otariids gradually molt all year. [116] Elephant seal males establish dominance hierarchies with the highest ranking malesthe alpha malesmaintaining harems of as many as 30100 females. Heat from the arterial blood is transferred to the blood vessels, which then recirculate blood back to the core. In one legend, seals, whales and other marine mammals were formed from her severed fingers. (3,855.5 kilograms). Navy officials say that the sea lions can do this in seconds, before the enemy realizes what happened. [183] In 2010 and 2011, sea ice in the Northwest Atlantic was at or near an all-time low and harp seals as well as ringed seals that bred on thin ice saw increased death rates. Dugong. They can also dive 1,500m (4,900ft) and for as long as 77minutes. Ralls, K.; Mesnick, S. "Sexual dimorphism" in, Lavinge, D. M.; Kovacs, K. M.; Bonner, W. N. "Seals and Sea lions" in, Weller, D. W. "Predation on marine mammals" in, Mesnick, S. L.; Ralls, K. "Mating systems" in, Sandergen, F. E. (1970). Territorial boundaries are usually marked by natural breaks in the substrate,[116] and some may be fully or partially underwater. The use of firearms in seal hunting during the modern era drastically increased the number of killings. The genera Phoca and Pusa could have arisen when a phocine lineage traveled from the Paratethys Sea to the Arctic Basin and subsequently went eastward. Although pinnipeds are widespread, most species prefer the colder waters of the Northern and Southern Hemispheres. Other popularly kept species include the grey seal and harbor seal. The largest is the southern elephant seal. [158] Seals are also of great importance in the culture of the Inuit. The severe decline of sealing worldwide after World War II and the effects of international agreements aimed at conserving breeding stocks enabled several severely depleted species to replenish their numbers. Solitary foraging species usually exploit coastal waters, bays and rivers. [150] These differences are likely important for mothers and pups who need to remain in contact on crowded beaches. [32], In a match-to-sample task study, a single California sea lion was able to demonstrate an understanding of symmetry, transitivity and equivalence; a second seal was unable to complete the tasks. seal, any of 32 species of web-footed aquatic mammals that live chiefly in cold seas and whose body shape, round at the middle and tapered at the ends, is adapted to swift and graceful swimming. [180], Pinnipeds face various threats. [169] The Navy insists that the sea lions are removed once their mission is complete. Seal hunting, or sealing, was so widespread and indiscriminate in the 19th century that many species might have become extinct if international regulations had not been enacted for their protection. The skins of fur seals and phocids are made into coats, and the tusks of walruses continue to be used for carvings or as ornaments. The males arrive earlier in the season and wait for them. Seal - Classification | Britannica Eared seals, on the other hand, rely mainly on a rowing motion of their front flippers for propulsion. The northern elephant seal was hunted to near extinction in the late 19th century, with only a small population remaining on Guadalupe Island. [168] Organizations like PETA believe that such operations put the animals in danger. Gray Seal | NOAA Fisheries Deep-diving species such as elephant seals have blood volumes that represent up to 20% of their body weight. These are important for detecting their prey on the muddy sea floor. Types of Seals - Seal Facts and Information [85][86], Pinnipeds can produce a number of vocalizations such as barks, grunts, rasps, rattles, growls, creaks, warbles, trills, chirps, chugs, clicks and whistles. [78], Pinnipeds spend many months at a time at sea, so they must sleep in the water. [25], The lineages of Otariidae and Odobenidae split almost 28mya. [109] Of the 33species, 20breed on land, and the remaining 13breed on ice. Seals have been hunted for their meat, hides, oil, and fur. [14] A 2006 molecular study supports the division of phocids into two monophyletic subfamilies: Monachinae, which consists of Mirounga, Monachini and Lobodontini; and Phocinae, which includes Pusa, Phoca, Halichoerus, Histriophoca, Pagophilus, Erignathus and Cystophora. [42] Pinnipeds have several adaptions for reducing drag. [41] Some species leap out of the water, which may allow them to travel faster. [89] Ringed seals build dens underneath fast ice. [170], Humans have hunted seals since the Stone Age. [17], Odobenidae consists of only one living member: the modern walrus. Killer Whales and Sharks. 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). Humphead Wrasse. Enaliarctos was capable of swimming with both the fore-flippers and hind-flippers, but it may have been more specialized as a fore-flipper swimmer. Vocals are produced both in air and underwater. Originally, seals were hit with clubs during haul-out. An exception to this is the walrus, where females form dense aggregations perhaps due to their patchy food sources. Visual displays also occur: Weddell seals will make an S-shaped posture when patrolling under the ice, and Ross seals will display the stripes on their chests and teeth when approached. [172] National and international authorities have given special treatment to aboriginal hunters since their methods of killing are seen as less destructive and wasteful. 14 Seal Secrets | NOAA Fisheries 500 to 32,000Hz in the northern fur seal, compared to 20 to 20,000Hz in humans), their airborne hearing sensitivity is weaker overall. Currently, P. largha is widely recognized as a separate species. In addition, walruses feed solitarily but are often near other walruses in small or large groups that may surface and dive in unison. [17] Otariids originated in the North Pacific. The Baikal seal ( Phoca sibirica) of Lake Baikal in Siberia, Russia, is the smallest at 1.1-1.4 metres (3.6-4.6 feet) long and 50-130 kg (110-290 pounds), but some female fur seals weigh less. They typically last 57minutes with average depths to 3045m (98148ft). Order - Pinnipedia. Sea Turtle. Harbor Seal Large sharks are another major predator of pinnipedsusually the great white shark but also the tiger shark and mako shark. [81] Monk seals and some otariids live in tropical and subtropical waters. They have streamlined bodies and four limbs that are modified into flippers. In science, it is also sometimes restricted to the "true" seals of the family Phocidae. Pinnipeds are typically hunted for their meat and blubber. Indian spotted chevrotain is known as mouse deer is the smallest hoofed mammals in the world, found in the dense rainforests of India and Nepal. Because they are able to turn their hind flippers forward, they can use all four limbs when moving on land. [64] The vibrissae of phocids are undulated and wavy while otariid and walrus vibrissae are smooth. [121], With the exception of the walrus, which has five- to six-year-long inter-birth intervals, female pinnipeds enter estrous shortly after they give birth. [14] The monochines diversified southward. [96] The longest recorded lifespans include 43years for a wild female ringed seal and 46years for a wild female grey seal. [74] The heart of a seal is moderately flattened to allow the lungs to deflate. As in many mammals and birds, pinnipeds possess nictitating membranes. Various species are able to reach depths of 150250 metres or more and can remain underwater for 2030 minutes, with the Weddell seal diving for up to 73 minutes and up to 600 metres. Walruses and hooded seals are unique among ice-breeding species in that they have pronounced sexual dimorphism in favor of males. The IUCN declared it extinct in 1996. 18 species in 10 genera. [44] The fore-flippers move in a transverse, rather than a sagittal fashion. Credit: NOAA Fisheries Celebrate International Day of the Seal by learning a few facts about these semi-aquatic marine mammals. [55] Although pinnipeds have a fairly good sense of smell on land,[56] it is useless underwater as their nostrils are closed. They also have a well-developed tapetum lucidum, a reflecting layer that increases sensitivity by reflecting light back through the rods. More elaborate exhibits contain deep pools that can be viewed underwater with rock-mimicking cement as haul-out areas. These animals lack external ear flaps and are incapable of turning their hind-flippers forward, which makes them more cumbersome on land. Alternatively, this lineage may have spread from the North Pacific to the Arctic and subsequently the North Atlantic during the Pleistocene. The earliest fossils of OdobenidaePrototaria of Japan and Proneotherium of Oregondate to 1816mya. [164], Pinnipeds can be found in facilities around the world, as their large size and playfulness make them popular attractions. Teeth chattering, hisses and exhalations are also made as aggressive warnings. [63], Unlike terrestrial mammals, such as rodents, pinnipeds do not move their vibrissae over an object when examining it but instead extend their moveable whiskers and keep them in the same position. This term typically excludes the walrus in everyday English. [185], Some species have become so numerous that they conflict with local people. Seal Animal Facts | Phoca vitulina - AZ Animals [14] Compared to other carnivorans, their teeth tend to be fewer in number (especially incisors and back molars), are pointed and cone-shaped, and lack carnassials. Great White Shark. [137], Male pinnipeds generally play little role in raising the young. Dominant male elephant seals advertise their status and threaten rivals with "clap-threats" and loud drum-like calls[143] that may be modified by the proboscis.
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