59-403: 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 ( / 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
118-489: A greyish-brown natal fur with scattered patches of white on the back and head. The bearded seal is unique in the subfamily Phocinae in having two pairs of teats , a feature it shares with monk seals . Bearded seals reach about 2.1 to 2.7 m (6.9 to 8.9 ft) in nose-to-tail length and from 200 to 430 kg (441 to 948 lb) in weight. The female seal is larger than the male, meaning that they are sexually dimorphic . Bearded seals, along with ringed seals , are
177-626: 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
236-517: A major food source for polar bears . They are also an important food source for the Inuit of the Arctic coast . The Inuit language name for the seal is ugjuk (plural: ugjuit ) or oogrook or oogruk . The Inuit preferred the ringed seal for food and light; the meat would be eaten and the blubber burnt in the kudlik (stone lamp). The skin of the bearded seal is tougher than regular seal and
295-439: 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
354-540: A trill with a sound-pressure of at least 100 dB at 1 m in order for the sound to propagate 30 km, meaning that bearded seals can likely produce sounds at this level. On March 28, 2008, the U.S. National Marine Fisheries Service initiated a status review under the Endangered Species Act (ESA) to determine if listing this species under the ESA is warranted. All bearded seals are protected under
413-675: Is a vertebrate animal of the class Mammalia ( / m ə ˈ m eɪ l i . ə / ). Mammals are characterized by the presence of milk -producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair , and three middle ear bones . These characteristics distinguish them from reptiles and birds , from which their ancestors diverged in the Carboniferous Period over 300 million years ago. Around 6,400 extant species of mammals have been described and divided into 27 orders . The largest orders of mammals, by number of species , are
472-473: 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] Mammal A mammal (from Latin mamma 'breast')
531-516: Is different from that of other Northern Pacific phocids . A majority of the rings in the trachea are incomplete with only a membrane attaching the two ends. The sounds of the bearded seal usually consist of a long oscillating trill lasting for a minute or more followed by a short, deep moan. This "song" is often repeated frequently. The number of call types within a population can vary geographically, with four types found in Svalbard and eleven in
590-404: Is likely that females produce these sounds as well. Underwater, bearded seal trills can be heard from a distance of over 30 km (19 mi), with some types of sounds traveling farther than others. This makes it possible for one animal to communicate with another animal that is far away, although acoustic degradation does occur as the sound passes through the environment. A seal must produce
649-572: Is primarily driven by human poaching and habitat destruction , primarily deforestation . Over 70% of mammal species are in the orders Rodentia , Chiroptera , and Eulipotyphla . Mammal classification has been through several revisions since Carl Linnaeus initially defined the class, and at present , no classification system is universally accepted. McKenna & Bell (1997) and Wilson & Reeder (2005) provide useful recent compendiums. Simpson (1945) provides systematics of mammal origins and relationships that had been taught universally until
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#1732765442876708-426: Is the viviparous placental mammals , so named for the temporary organ ( placenta ) used by offspring to draw nutrition from the mother during gestation . Most mammals are intelligent , with some possessing large brains, self-awareness , and tool use . Mammals can communicate and vocalize in several ways, including the production of ultrasound , scent marking , alarm signals , singing , echolocation ; and, in
767-473: The Cretaceous . The relationships between these three lineages is contentious, and all three possible hypotheses have been proposed with respect to which group is basal . These hypotheses are Atlantogenata (basal Boreoeutheria), Epitheria (basal Xenarthra) and Exafroplacentalia (basal Afrotheria). Boreoeutheria in turn contains two major lineages— Euarchontoglires and Laurasiatheria . Estimates for
826-564: The International Union for Conservation of Nature (IUCN) completed a five-year Global Mammal Assessment for its IUCN Red List , which counted 5,488 species. According to research published in the Journal of Mammalogy in 2018, the number of recognized mammal species is 6,495, including 96 recently extinct. The word " mammal " is modern, from the scientific name Mammalia coined by Carl Linnaeus in 1758, derived from
885-556: The Latin mamma ("teat, pap"). In an influential 1988 paper, Timothy Rowe defined Mammalia phylogenetically as the crown group of mammals, the clade consisting of the most recent common ancestor of living monotremes ( echidnas and platypuses ) and therian mammals ( marsupials and placentals ) and all descendants of that ancestor. Since this ancestor lived in the Jurassic period, Rowe's definition excludes all animals from
944-908: The Marine Mammal Protection Act , and determined by the IUCN to be classified as a "least concern" for extinction. This classification was determined due to various factors including, widespread distribution, stable population size, as well as alternating prey resources. NOAA determined that the factors influencing any change in conservancy status of the bearded seal may include: loss of sea ice by climate change, bycatch from commercial fishing gear, and hunting. Their main predators include polar bears ; however, typically pups around age 2 are attacked within birthing lairs, leaving older juveniles and adults commonly unharmed. Due to climate change, factors such as loss of sea ice, as well as decrease in prey population may create negative results on
1003-459: The Pleistocene epoch, bearded seals ranged as far south as South Carolina . Distinguishing features of this earless seal include square fore flippers and thick bristles on its muzzle. Adults are greyish-brown in colour, darker on the back; rarely with a few faint spots on the back or dark spots on the sides. Occasionally the face and neck are reddish brown. Bearded seal pups are born with
1062-606: The biological classification scheme used, are the primates : apes , monkeys , and lemurs ; the Cetartiodactyla : whales and even-toed ungulates ; and the Carnivora which includes cats , dogs , weasels , bears , seals , and allies. According to Mammal Species of the World , 5,416 species were identified in 2006. These were grouped into 1,229 genera , 153 families and 29 orders. In 2008,
1121-406: The dominant terrestrial animal group from 66 million years ago to the present. The basic mammalian body type is quadrupedal , with most mammals using four limbs for terrestrial locomotion ; but in some, the limbs are adapted for life at sea , in the air , in trees or underground . The bipeds have adapted to move using only the two lower limbs, while the rear limbs of cetaceans and
1180-480: 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
1239-428: The rodents , bats , and Eulipotyphla (including hedgehogs , moles and shrews ). The next three are the primates (including humans , monkeys and lemurs ), the even-toed ungulates (including pigs , camels , and whales ), and the Carnivora (including cats , dogs , and seals ). Mammals are the only living members of Synapsida ; this clade , together with Sauropsida (reptiles and birds), constitutes
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#17327654428761298-439: The sea cows are mere internal vestiges . Mammals range in size from the 30–40 millimetres (1.2–1.6 in) bumblebee bat to the 30 metres (98 ft) blue whale —possibly the largest animal to have ever lived. Maximum lifespan varies from two years for the shrew to 211 years for the bowhead whale . All modern mammals give birth to live young, except the five species of monotremes , which lay eggs. The most species-rich group
1357-463: The square flipper seal , is a medium-sized pinniped that is found in and near to the Arctic Ocean . It gets its generic name from two Greek words ( eri and gnathos ) that refer to its heavy jaw. The other part of its Linnaean name means bearded and refers to its most characteristic feature, the conspicuous and very abundant whiskers. When dry, these whiskers curl very elegantly, giving
1416-457: 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
1475-567: 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
1534-728: The Alaskan coast to the Sea of Okhotsk on the Russian coast, up to but not including the northern coast of Japan. In the Arctic Ocean , they are found along the northern coasts of Russia , Norway , Canada , and Alaska , including the Norwegian Archipelago of Svalbard and Canadian Arctic Archipelago . In the Atlantic, Bearded seals are found along the northern coast of Iceland , the east and west coasts of Greenland and
1593-621: The Canadian mainland as far south as Labrador . Although the range typically only extends down into subarctic areas bearded seals have been seen in Japan and China as well as extremely far south of their range in Germany, Netherlands, United Kingdom, France, Spain and Portugal. Primarily benthic , bearded seals feed on a variety of small prey found along the ocean floor, including clams , squid , and fish . Their whiskers serve as feelers in
1652-902: 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 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
1711-688: The Western Canadian Arctic. The most frequent sounds are trills, moans, and sweeps. A sweep can be compared to a short trill. Bearded seals produce distinct trills from late March to late June, with a decline in rhythmicity in late May and June. This timeline coincides with their breeding and pupping season, which is from April to May. The repetitive and transmittable nature of bearded seal trills leads researchers to believe that they are utilized for communication, likely during courtship and breeding. Males use these sounds to establish mating territories and communicate their fitness, but it
1770-595: The bearded seal a "raffish" look. Bearded seals are the largest northern phocid. They have been found to weigh as much as 300 kg (660 lb) with the females being the largest. However, male and female bearded seals are not very dimorphic . The only member of the genus Erignathus , the bearded seal is unique in that it is an intermediate. Bearded seals belong to the family Phocidae which contains two subfamilies: Phocinae and Monachinae . The bearded seal possesses characteristics of both of these subfamilies. Fossils first described in 2002 indicate that, during
1829-402: The bearded seal include polar bears, who rely on these seals as a major food source. Killer whales also prey on these seals, sometimes overturning ice floes to reach them. Walruses also eat these seals, mainly pups, but such predation is rare. Bearded seals are believed to live up to 31 years. The vocalizations produced by the bearded seal are very unique, possibly because their trachea
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1888-477: The bearded seal population in the future. Therefore, monitoring of the species as well as influences of human activity, will be vital to ensure species stability. There are two recognized subspecies of this seal: While the validity of these subspecies has been questioned, and is not yet supported by any molecular data, analysis of the animals' calls does indicate a differentiation between different populations. Bearded seal fossils have been found to be as old as
1947-411: 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
2006-492: The case of humans, complex language . Mammals can organize themselves into fission–fusion societies , harems , and hierarchies —but can also be solitary and territorial . Most mammals are polygynous , but some can be monogamous or polyandrous . Domestication of many types of mammals by humans played a major role in the Neolithic Revolution , and resulted in farming replacing hunting and gathering as
2065-812: The clade originating with the last common ancestor of Sinoconodon and living mammals. The earliest-known synapsid satisfying Kemp's definitions is Tikitherium , dated 225 Ma , so the appearance of mammals in this broader sense can be given this Late Triassic date. However, this animal may have actually evolved during the Neogene. As of the early 21st century, molecular studies based on DNA analysis have suggested new relationships among mammal families. Most of these findings have been independently validated by retrotransposon presence/absence data . Classification systems based on molecular studies reveal three major groups or lineages of placental mammals— Afrotheria , Xenarthra and Boreoeutheria —which diverged in
2124-444: The closest thing to an official classification of mammals, despite its known issues. Most mammals, including the six most species-rich orders , belong to the placental group. The three largest orders in numbers of species are Rodentia : mice , rats , porcupines , beavers , capybaras , and other gnawing mammals; Chiroptera : bats; and Eulipotyphla : shrews , moles , and solenodons . The next three biggest orders, depending on
2183-489: 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
2242-400: The diphylectic hypothesis. One such study suggests that phocids are sister taxa to the common ancestor to both otariids and odobenids. Bearded seals belong to the subfamily Phocinae (Northern Hemisphere seals). Phocinae can be further divided into three clades: Erignathini (bearded seals), Cystophorini (hooded seals), and Phocini (all remaining genera). Bearded seals are the sister taxa to
2301-1358: The divergence times between these three placental groups range from 105 to 120 million years ago, depending on the type of DNA used (such as nuclear or mitochondrial ) and varying interpretations of paleogeographic data. Monotremata Marsupialia Xenarthra Afrotheria Glires Euarchonta [REDACTED] Eulipotyphla Chiroptera Pholidota Carnivora [REDACTED] Perissodactyla [REDACTED] Artiodactyla [REDACTED] Monotremata [REDACTED] Paucituberculata [REDACTED] Didelphimorphia [REDACTED] Microbiotheria Notoryctemorphia [REDACTED] Peramelemorphia [REDACTED] Dasyuromorphia [REDACTED] Diprotodontia [REDACTED] Cingulata [REDACTED] Pilosa [REDACTED] Hyracoidea [REDACTED] Sirenia [REDACTED] Proboscidea [REDACTED] Tubulidentata [REDACTED] Macroscelidea [REDACTED] Afrosoricida [REDACTED] Eulipotyphla [REDACTED] Chiroptera [REDACTED] Pholidota [REDACTED] Carnivora [REDACTED] Perissodactyla [REDACTED] Artiodactyla [REDACTED] Scandentia [REDACTED] Lagomorpha [REDACTED] Bearded seal The bearded seal ( Erignathus barbatus ), also called
2360-585: The earlier Triassic , despite the fact that Triassic fossils in the Haramiyida have been referred to the Mammalia since the mid-19th century. If Mammalia is considered as the crown group, its origin can be roughly dated as the first known appearance of animals more closely related to some extant mammals than to others. Ambondro is more closely related to monotremes than to therian mammals while Amphilestes and Amphitherium are more closely related to
2419-531: The early to mid Pleistocene . These early fossils were found in northern regions like England, Alaska, and Sweden, as well as the North Sea and the Champlain Sea . Bearded seals, like all true seals, belong to the family Phocidae which is one of the three families in the clade Pinnipedia, along with Otariidae and Odobenidae . Pinnipeds are thought to have originated 27 to 25 million years ago during
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2478-451: The end of the 20th century. However, since 1945, a large amount of new and more detailed information has gradually been found: The paleontological record has been recalibrated, and the intervening years have seen much debate and progress concerning the theoretical underpinnings of systematization itself, partly through the new concept of cladistics . Though fieldwork and lab work progressively outdated Simpson's classification, it remains
2537-410: 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 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
2596-668: The larger Amniota clade. Early synapsids are referred to as " pelycosaurs ." The more advanced therapsids became dominant during the Guadalupian . Mammals originated from cynodonts , an advanced group of therapsids, during the Late Triassic to Early Jurassic . Mammals achieved their modern diversity in the Paleogene and Neogene periods of the Cenozoic era, after the extinction of non-avian dinosaurs , and have been
2655-671: The largest fish consumed by the seals. Bearded seals are capable of preying on pelagic and demersal fish in addition to their benthic prey. Bearded seals give birth in the spring. In the Canadian Arctic , seal pupping occurs in May. In Svalbard, bearded seals reach sexual maturity at 5 or 6 years of age. Further south, in Alaska , most pups are born in late April. Pups are born on small drifting ice floes in shallow waters, usually weighing around 30–40 kg (66–88 lb). They enter
2714-407: The late Oligocene period. One hypothesis for the evolution of pinnipeds is that pinnipeds are a diphyletic group and otariids and odobenids are more closely related to bears, and phocids are more closely related to mustelids like weasels. Another hypothesis suggests that pinnipeds are a monophyletic group that descended from a single ancestor. This has been more supported by phylogenetic analysis than
2773-480: 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
2832-505: 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 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
2891-676: 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
2950-522: 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
3009-716: The primary source of food for humans. This led to a major restructuring of human societies from nomadic to sedentary, with more co-operation among larger and larger groups, and ultimately the development of the first civilizations . Domesticated mammals provided, and continue to provide, power for transport and agriculture, as well as food ( meat and dairy products ), fur , and leather . Mammals are also hunted and raced for sport, kept as pets and working animals of various types, and are used as model organisms in science. Mammals have been depicted in art since Paleolithic times, and appear in literature, film, mythology, and religion. Decline in numbers and extinction of many mammals
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#17327654428763068-434: The pups are weaned, a new mating cycle takes place. Females ovulate at the end of their lactation period, but remain close to their pups, ready to defend them if necessary. During the mating season, male seals will "sing", emitting a long-drawn-out warbling note that ends in a sort of moan or sigh. This sound may attract females, or may be used by the males to proclaim their territory or their readiness for breeding. Males occupy
3127-466: The same areas from one year to the next. Like many Arctic mammals, bearded seals employ a reproductive strategy known as delayed implantation . This means that the blastocyst is not implanted for two months after fertilization, most often becoming implanted in July. Thus, the seal's total gestation period is around eleven months, though its active gestation period is nine months. Natural predators of
3186-431: 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
3245-521: The soft bottom sediments. Adults tend not to dive very deep, favoring shallow coastal areas no more than 300 m (980 ft) deep. Pups up to one year old, however, will venture much deeper, diving as deep as 450 m (1,480 ft). In a study conducted during the summer months, the seals have been found to feed on invertebrates such as anemones , sea cucumbers , and polychaete worms . The same study found that sculpins and Arctic cod made up most of their summer diet. Sculpin were also found to be
3304-548: The therians; as fossils of all three genera are dated about 167 million years ago in the Middle Jurassic , this is a reasonable estimate for the appearance of the crown group. T. S. Kemp has provided a more traditional definition: " Synapsids that possess a dentary – squamosal jaw articulation and occlusion between upper and lower molars with a transverse component to the movement" or, equivalently in Kemp's view,
3363-399: 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
3422-424: The water only hours after they are born, and quickly become proficient divers. Mothers care for the pups for 18–24 days, during which time the pups grow at an average rate of 3.3 kg (7.3 lb) per day. During this time, pups consume an average of 8 L (1.8 imp gal; 2.1 US gal) of milk a day. By the time they are weaned, the pups have grown to about 100 kg (220 lb). Just before
3481-631: Was used to make shoes, whips, dog sled harnesses, to cover a wooden frame boat, the Umiak and in constructing summer tents known as tupiq . The body fat content of a bearded seal is about 25–40%. Bearded seals are extant in Arctic and subarctic regions. In the Pacific region, they extend from the Chukchi Sea in the Arctic, south into the Bering Sea where they span from Bristol Bay on
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