38-582: Larga may refer to several places in Romania: two places in Moldova: a species of true seal : a musical note value in mensural notation , also called the maxima . True 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 the family Phocidae ( / ˈ f oʊ s ɪ d iː / ). They are sometimes called crawling seals to distinguish them from
76-628: 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
114-446: A rate of about 4.2 kilograms (9.3 lb) a day, and grow to be around 100 kilograms (220 lb) when they are weaned at two or three weeks. These seals are covered mostly by brown or silver fur, with darker coloration around flippers. The color fades throughout the year, and recently molted seals appear darker than the silvery-white crabeater seals that are about to molt. Their body is comparatively more slender than other seals, and
152-439: 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
190-511: A significant proportion of weight as they attend to their mating partners and fight off rivals. During summer, males typically weigh 200 kilograms (440 lb), and females 215 kilograms (474 lb). A molecular genetic based technique has been established to confirm the sex of individuals in the laboratory. Large crabeater seals can weigh up to 300 kg (660 lb). Pups are about 1.2 metres (3.9 ft) in length and 20 to 30 kilograms (44 to 66 lb) at birth. While nursing, pups grow at
228-514: A subadult coat similar to the adult pelage. Curiously, crabeater seals have been known to wander further inland than any other pinniped. Carcasses have been found over 100 km (62 mi) from the water and over 1,000 m (3,300 ft) above sea level, where they can be mummified in the dry, cold air and conserved for centuries. Despite the common name of the species, the crabeater seal does not feed on crabs (the few crab species in its range are mostly found in very deep water ). Rather, it
266-547: A year in the 20th century, due to the removal of large baleen whales (especially the blue whale) during the period of industrial whaling and the subsequent explosion in krill biomass and removal of important competitive forces. Young crabeater seals experience significant predation by leopard seals. Indeed, first-year mortality is exceedingly high, possibly reaching 80%, and up to 78% of crabeaters that survive through their first year have injuries and scars from leopard seal attacks. Long scars and sets of parallel scars, visible on
304-432: Is a specialist predator on Antarctic krill ( Euphausia superba ), which comprise over 90% of the diet. Their high abundance is a testament to the extreme success of Antarctic krill, the single species with the greatest biomass on the planet. There is little seasonality in their prey preference, but they may target adult and male krill. Other prey items include cephalopods and diverse Antarctic fish species. Although
342-507: 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] Crabeater seal Lobodon carcinophagus The crabeater seal ( Lobodon carcinophaga ), also known as
380-436: Is the unique dentition that enables this species to sieve Antarctic krill. The postcanine teeth are finely divided with multiple cusps. Together with the tight fit of the upper and lower jaw, a bony protuberance near the back of the mouth completes a near-perfect sieve within which krill are trapped. Crabeater seals have a continuous circumpolar distribution surrounding Antarctica, with only occasional sightings or strandings in
418-486: 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 is Noriphoca gaudini from the late Oligocene or earliest Miocene ( Aquitanian ) of Italy . Other early fossil phocids date from
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#1733085307756456-513: The krill-eater seal , is a true seal with a circumpolar distribution around the coast of Antarctica . They are the only member of the genus Lobodon . They are medium- to large-sized (over 2 m in length), relatively slender and pale-colored, found primarily on the free-floating pack ice that extends seasonally out from the Antarctic coast, which they use as a platform for resting, mating, social aggregation and accessing their prey. They are by far
494-956: 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 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
532-480: 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
570-660: The species name carcinophaga means "crab eater." The crabeater seal shares a common recent ancestor with the other Antarctic seals, which are together known as the lobodontine seals . These include the leopard seal ( Hydrurga leptonyx ), the Ross seal ( Ommatophoca rossii ), and the Weddell seal ( Leptonychotes weddelli ). These species, collectively belonging to the Lobodontini tribe of seals, share teeth adaptations including lobes and cusps useful for straining smaller prey items out of
608-459: 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
646-565: 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
684-856: The Antarctic Pack Ice Seal initiative, is currently underway to evaluate systematically collected survey data and obtain reliable estimates of all Antarctic seal abundances. Crabeater seals have a typical, serpentine gait when on ice or land, combining retractions of the foreflippers with undulations of the lumbar region. This method of locomotion leaves a distinctive sinuous body track and can be extremely effective. When not subject to overheating (i.e. on cold days), speeds on land of 19–26 km/h (12–16 mph) have been recorded for short distances. Satellite tracking data have resulted in conservative estimates of swimming speeds of 66 km/day and 12.7 km/h. While swimming, crabeaters have been known to engage in porpoising (leaping entirely out of
722-411: 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
760-548: The crabeater seal is sympatric with the other Antarctic seal species (Weddell, Ross and leopard seals), the specialization on krill minimizes interspecific food competition. Among krill-feeding whales , only blue whales ( Balaenoptera musculus ) and minke whales ( B. acutorostrata ) extend their range as far south as the pack ice where the crabeater seals are most frequent. While no reliable historical population estimates have been done, population models suggest crabeater seal populations may have increased at rates up to 9%
798-489: 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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#1733085307756836-407: The extreme southern coasts of Argentina , South Africa , Australia and New Zealand . They spend the entire year on the pack ice zone as it advances and retreats seasonally, primarily staying within the continental shelf area in waters less than 600 m (2,000 ft) deep. They colonized Antarctica during the late Miocene or early Pliocene (15–25 million years ago), at a time when
874-400: The finely lobed teeth adapted to filtering their small crustacean prey. Despite its name, the crabeater seal does not eat crabs. As well as being an important krill predator, the crabeater seal's pups are an important component of the diet of leopard seals ( H. leptonyx ). The genus name of the crabeater seal, Lobodon , derives from Ancient Greek meaning "lobe-toothed", and
912-548: The first molt at weaning. Younger animals are marked by net-like, chocolate brown markings and flecks on the shoulders, sides and flanks, shading into the predominantly dark hind and fore flippers and head, often due to scarring from leopard seals . After molting, their fur is a darker brown fading to blonde on their bellies. The fur lightens throughout the year, becoming completely blonde in summer. Crabeaters have relatively slender bodies and long skulls and snouts compared to other phocids. Perhaps their most distinctive adaptation
950-498: The ice or in the water. Crabeater seals give birth during the Antarctic spring from September to December. Rather than aggregate in reproductive rookeries , females haul out on ice to give birth singly. Adult males attend female-pup pairs until the female begins estrus one to two weeks after the pup is weaned before mating. Copulation has not been observed directly and presumably occurs in water. Pups are weaned in about three weeks, at which time they are also beginning to molt into
988-436: 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 a monophyletic origin for all pinnipeds from a single ancestor, possibly Enaliarctos , most closely related to
1026-540: The most abundant seal species in the world. While population estimates are uncertain, there are at least 7 million and possibly as many as 75 million individuals. This success of this species is due to its specialized predation on the abundant Antarctic krill of the Southern Ocean , for which it has uniquely adapted, sieve-like tooth structure. Indeed, its scientific name, translated as "lobe-toothed ( lobodon ) crab eater ( carcinophaga )", refers specifically to
1064-480: 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
1102-728: 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
1140-499: The otherwise pale and relatively unmarked pelage of crabeaters, are present on nearly all young seals. The incidence of visible scars falls off significantly after the first year, suggesting leopard seals primarily target the young of the year. The high predation pressure has clear impacts on the demography and life history of crabeater seals, and has likely had an important role in shaping social behaviors, including aggregation of subadults. Predation by killer whales ( Orcinus orca )
1178-523: 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
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1216-428: The region was much warmer than today. The population is connected and fairly well mixed ( panmictic ), and genetic evidence does not suggest any subspecies separations. A genetic survey did not detect evidence of a recent, sustained genetic bottleneck in this species, which suggests that populations do not appear to have suffered a substantial and sustained decline in the recent past. Currently, no reliable estimates of
1254-432: 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
1292-405: The snout is pointed. Crabeater seals can raise their heads and arch their backs while on ice, and they are able to move quickly if not subject to overheating. Crabeater seals exhibit scarring either from leopard seal attacks around the flippers or, for males, during the breeding season while fighting for mates around the throat and jaw. Pups are born with a light brown, downy pelage ( lanugo ), until
1330-400: 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
1368-493: The total crabeater seal population are available. Past estimates relied on minimal opportunistic sighting and much speculation, ranging from 2 million to 50–75 million individuals. Genetic evidence suggests that crabeater population numbers may have increased during the Pleistocene. The most recent point estimate is 7 million individuals, but this, too, is considered a likely underestimate. An international effort,
1406-716: The water column. The ancestral Lobodontini likely diverged from their sister clade , the Mirounga (elephant seals) in the late Miocene to early Pliocene , when they migrated southward and diversified rapidly in the relative isolation around Antarctica. Adult seals (over five years old) grow to an average length of 2.3 m (7.5 ft) and an average weight of around 200 kg (440 lb). Females are on average 6 cm (2.4 in) longer and around 8 kilograms (18 lb) heavier than males, though their weights fluctuate substantially according to season; females can lose up to 50% of their body weight during lactation, and males lose
1444-479: The water) and spyhopping (raising the body vertically out of the water for visual inspection) behaviors. The most gregarious of the Antarctic seals, crabeaters have been observed on the ice in aggregations of up to 1,000 hauled out animals and in swimming groups of several hundred individuals, breathing and diving almost synchronously. These aggregations consist primarily of younger animals. Adults are more typically encountered alone or in small groups of up to three on
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