The Weddell seal (Leptonychotes weddellii ) is a relatively large and abundant true seal with a circumpolar distribution surrounding Antarctica. The Weddell seal was discovered and named in the 1820s during expeditions led by British sealing captain James Weddell to the area of the Southern Ocean now known as the Weddell Sea. The life history of this species is well documented since it occupies fast ice environments close to the Antarctic continent and often adjacent to Antarctic bases.
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NocturnalNocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal",...
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CarnivoreA carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of a...
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PiscivoresA piscivore is a carnivorous animal that eats primarily fish. Piscivorous is equivalent to the Greek-derived word ichthyophagous. Fish were the die...
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MolluscivoreA molluscivore is a carnivorous animal that specializes in feeding on molluscs such as gastropods, bivalves, brachiopods, and cephalopods. Known mo...
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SemiaquaticSemiaquatic animals are those that are primarily or partly terrestrial but that spend a large amount of time swimming or otherwise occupied in wate...
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PrecocialPrecocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. Precocial species are normall...
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Apex predatorAn apex predator, also known as a top predator, is a predator at the top of a food chain and has no natural predators. These animals usually occup...
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NatatorialNatatorial animals are those adapted for swimming. Some fish use their pectoral fins as the primary means of locomotion, sometimes termed labriform...
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NomadicNomadic animals regularly move to and from the same areas within a well-defined range. Most animals travel in groups in search of better territorie...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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CongregatoryCongregatory animals tend to gather in large numbers in specific areas as breeding colonies, for feeding, or for resting.
Among animals, viviparity is the development of the embryo inside the body of the parent. The term 'viviparity' and its adjective form 'viviparous'...
Sedentary animals lead such a type of lifestyle in which little to or no physical activity is done. These are mostly marine bottom-dwelling animals...
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PolygynyPolygyny is a mating system in which one male lives and mates with multiple females but each female only mates with a single male.
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Generally solitaryGenerally solitary animals are those animals that spend their time separately but will gather at foraging areas or sleep in the same location or sh...
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ColonialColonial animals live in large aggregations composed of two or more conspecific individuals in close association with or connected to, one another....
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Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withThe Weddell seal is a large seal with a bulky body, and a relatively small head with a short, wide snout. Adults are brown to dark gray with light and dark patches on the back and silvery-white on the belly. The front flippers are smallish relative to body size. The fur color of pups is light gray or sometimes golden.
Weddell seals inhabit Antarctic and sub-Antarctic waters. They do not migrate and winters are spent under the ice of the Antarctic Sea, emerging through blowholes and cracks to breathe. They congregate in large groups on pack ice. They are found in areas further south than all other mammals, 1,287 km (800 miles) distant from the South Pole in McMurdo Sound waters.
Outside of the breeding season Weddell seals usually spend time singly but tend to form small groups around breathing holes and cracks in the ice. This is its lifeline, as the hole is essential for both resurfacing for air and diving for food. When on ice, a seal will rarely travel more than three meters away from its hole. Most of its activities happen at night under water. The seals can dive down as far a 600 m, and stay under water for as long as an hour. They are especially noisy underwater, with a constant barrage of sounds. Vocalizations made by the male are more complex than the female's noises and can be heard as far as 20 miles away. Such sounds could be for territorial defense.
Weddel seals are carnivores (piscivores) and their diet includes mostly fish and squid. In summer, they hunt a little more at night and dive to forage for food. They get enough water from metabolizing seawater or from their food but sometimes individuals will eat snow.
Weddell seals return to fast ice colonies during the spring for birthing and breeding. It is suggested that they are polygynous breeders and don't form pairs. Birthing occurs from September to December after the gestation period of 9-10 months. A single pup is usually born but sometimes twins are produced. The mother and pup then stay together. The pups first enter the water around 1-2 weeks old. Breeding males stay in the water under the ice, defending territory and a breathing hole until pups are weaned at 6 weeks old. The pup is then left to learn to hunt. The mother goes off to mate again. Weddell seal females become reproductively mature as early as 3 years old, but both females and males don't usually breed until they're about 7.
Weddell seals face no immediate or significant threats. Potential threats are climate change and global warming. Weddell seal numbers may decline with increasing temperatures if Antarctic sea ice is significantly reduced. Disturbance by vessel noise and a close approach by people may also harm this seal.
According to IUCN, the global population of Weddell seals has been variously estimated at 200,000 to 1,000,000 individuals. The ICUN classifies the Weddell seal as "Least Concern".