- Related Topics:
- seal
- Enaliarctos
- earless seal
- Odobenidae
- eared seal
pinniped
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What are pinnipeds?
Pinnipeds (suborder Pinnipedia) are aquatic, fin-footed mammals that include seals, sea lions, and the walrus. The word pinniped means “feather-foot” in Latin, referring to their winglike flippers.
Pinnipeds possess wide torsos and narrower hindquarters and are swift and graceful in the water but awkward on land. They have slitlike nostrils that can be closed underwater, and their ears are either small or entirely absent. All have short fur, with the walrus having almost none, and a vestigial tail. They are visual predators that eat a strictly carnivorous diet.
Pinnipedia is often considered a separate order from other carnivores (order Carnivora) and derived from a common bearlike ancestor approximately 25 to 27 million years ago.
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Which animals belong to the pinniped group?
Pinnipeds are a suborder of aquatic mammals that consist of 33-34 species. They are divided into three families:
* Phocidae: True seals, also known as earless seals, including harbor, harp, and elephant seals.
* Otariidae: Fur seals and sea lions, also known as eared seals, such as the California sea lion and the Steller sea lion.
* Odobenidae: Walruses.Pinnipeds are well-adapted for marine life, with streamlined bodies and flippers for swimming, but they are also capable of moving on land, though often awkwardly.
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Where do pinnipeds live?
Pinnipeds, comprising seals, sea lions, and the walrus, are aquatic mammals that live in marine environments and some inland or tropical freshwater systems. Though especially abundant in polar seas, seals are found throughout the world, with some species favouring the open ocean and others inhabiting coastal waters or spending time on islands, shores, or ice floes.
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What adaptations help pinnipeds live in water?
Pinnipeds, such as seals, sea lions, and walruses, have several adaptations that allow them to thrive in aquatic environments. Their torpedo-shaped bodies and powerful flippers make them swift and graceful swimmers, easily capturing fish in open water. They can close their slitlike nostrils while underwater. Pinnipeds have short fur (except for walruses, who have almost none). Though some lack external ears, their hearing is excellent, especially underwater. Sensitive whiskers further aid in detecting prey.
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How are seals, sea lions, and walruses different from each other?
Seals, sea lions, and walruses are all pinnipeds, but they belong to different families and have distinct characteristics. Sea lions (Otariidae) have external ear flaps, long flippers, can rotate their hind flippers to walk on land, and are noisy, communicating through barks. True seals (Phocidae) lack external ear flaps, have shorter flippers, move on land by flopping on their bellies, and are quieter, communicating through soft grunts. Walruses (Odobenidae) are easily distinguished by their large tusks. Both sea lions and walruses use their forelimbs for propulsion, while true seals use their hind flippers.
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Why are some pinniped species threatened or endangered today?
Several pinniped species face threats and endangerment today due to various factors. Human activities, such as habitat loss and degradation, unsustainable hunting, chemical pollution, and the growing influence of global warming, pose significant risks.
For example, the sea otter was once hunted for its waterproof coat, which almost led to its extinction. Some pinniped species are also hunted by humans for their skin, meat, and blubber. Other threats include natural phenomena such as killer whale predation and anthropogenic factors such as oil spills.
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pinniped, (suborder Pinnipedia), any of a group of 34 species of aquatic fin-footed mammals comprising seals, sea lions, and the walrus. Pinnipeds live only in rich marine environments and a few inland or tropical freshwater systems.
Shaped like torpedoes, pinnipeds have wide torsos and narrower hindquarters. They are extremely awkward on land but swift and graceful in the water. Their slitlike nostrils can be closed underwater, and externally the ears are either small or entirely absent. All have short fur, the walrus having almost none, and the tail is vestigial. Length ranges from 1.1–1.4 meters (3.6–4.6 feet) in Baikal seals and Caspian seals to 6.5 metres (3.6 to 21 feet) in elephant seals, and weights range from about 30 kg (66 pounds) in some female fur seals to 3,700 kg in male elephant seals (genus Mirounga).
Natural history
Fur seals and sea lions (family Otariidae) and walrus (family Odobenidae) use their sizable forelimbs for propulsion, whereas true, or earless, seals (family Phocidae) use mostly the hind flippers. Despite the great size of some species, all are agile and easily capture fish in open water. Pinnipeds are visual predators, and, even though they may lack external ears, they generally have excellent hearing, especially underwater. All pinnipeds also have sensitive whiskers that help them detect prey. Diet is strictly carnivorous, but pinnipeds eat a variety of prey ranging in size from krill, which is filtered from the water by the complex cheek teeth, to, in the case of the leopard seal (Hydrurga leptonyx), penguins and even other pinnipeds. Most, however, rely primarily on fish, crustaceans (crabs, lobsters, shrimp), cephalopods (squid and octopus), and mollusks (shellfish).
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Pinnipeds such as the Ross seal (Ommatophoca rossii) may be solitary at certain times of the year, but most are usually gregarious, much more so than terrestrial carnivores. During the breeding season more than a million may congregate on an island. Males are sometimes larger than females, and among elephant seals males can be five times larger. Their greater size allows them to better defend harems of many females. In other pinnipeds the sexes are similar in size. Most males mate with multiple females, but some pinnipeds are monogamous. Mating and birth occur on coastal land or ice or on ice floes. Implantation of the fertilized eggs is delayed, with the result that gestation can last from 8 to 15 months. Young seals are called pups, and single offspring are the rule, with twins occurring rarely. At birth pups are often a different colour than their parents. After the breeding season most pinnipeds are pelagic (open-sea dwellers), traveling long distances either alone or in small groups, though some species do not migrate from the breeding grounds. The young mature in less than 6 years (longer in walrus), and some species can live more than 30 years in the wild. They are preyed upon by sharks, killer whales, leopard seals, and polar bears. Pinnipeds are also hunted by humans for their skin, meat, and fat (blubber). Walrus are also hunted for their ivory tusks.
Classification and paleontology
The word pinniped means “feather-foot” in Latin, a reference to the winglike flippers. As a group, Pinnipedia is often considered a separate order distinct from other carnivores (order Carnivora). Pinnipeds derived from a common bearlike ancestor during the late Oligocene Epoch, diverging some 25 to 27 million years ago into the presently known families.