Cosma / Communication / Knowledge / Realm / Terrestrial / Life /Animal / Mammal / Seal
—————————
Introduction1
Dictionary
seal : any of numerous carnivorous marine mammals (families Phocidae and Otariidae) that live chiefly in cold regions and have limbs modified into webbed flippers adapted primarily to swimming — Webster
OneLook, Free Dictionary, Wiktionary
Encyclopedia
Seals, scientifically known as Pinnipeds, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic marine mammals. They comprise the extant families Odobenidae (whose only living member is the walrus), Otariidae (the eared seals: sea lions and fur seals), and Phocidae (the earless seals, or true seals). There are 33 extant species of pinnipeds, and more than 50 extinct species have been described from fossils. 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). Pinnipeds belong to the order Carnivora and their closest living relatives are bears and musteloids (weasels, raccoons, skunks, and red pandas), having diverged about 50 million years ago.
Seals range in size from the 1 m (3 ft 3 in) and 45 kg (99 lb) Baikal seal to the 5 m (16 ft) and 3,200 kg (7,100 lb) southern elephant seal, which is also the largest member of the order Carnivora. Several species exhibit sexual dimorphism. They have streamlined bodies and four limbs that are modified into flippers. Though not as fast in the water as dolphins, seals are more flexible and agile. Otariids use their front limbs primarily to propel themselves through the water, while phocids and walruses use their hind limbs. Otariids and walruses have hind limbs that can be pulled under the body and used as legs on land. By comparison, terrestrial locomotion by phocids is more cumbersome. Otariids have visible external ears, while phocids and walruses lack these. Pinnipeds have well-developed senses—their eyesight and hearing are adapted for both air and water, and they have an advanced tactile system in their whiskers or vibrissae. Some species are well adapted for diving to great depths. They have a layer of fat, or blubber, under the skin to keep warm in the cold water, and, other than the walrus, all species are covered in fur.
Although pinnipeds are widespread, most species prefer the colder waters of the Northern and Southern Hemispheres. 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 killer whales. They feed largely on fish and marine invertebrates; but a few, like the leopard seal, feed on large vertebrates, such as penguins and other seals. Walruses are specialized for feeding on bottom-dwelling mollusks. Male pinnipeds typically mate with more than one female (polygyny), although the degree of polygyny varies with the species. The males of land-breeding species tend to mate with a greater number of females than those of ice breeding species. Male pinniped strategies for reproductive success vary between defending females, defending territories that attract females and performing ritual displays or lek mating. Pups are typically born in the spring and summer months and females bear almost all the responsibility for raising them. Mothers of some species fast and nurse their young for a relatively short period of time while others take foraging trips at sea between nursing bouts. Seals produce a number of vocalizations, notably the barks of California sea lions and the complex songs of Weddell seals. — Wikipedia
Search
————————–
Preservation
Library
WorldCat, Library of Congress, UPenn Online Books, Open Library
—————————
Participation
Education
Course
OER Commons: Open Educational Resources
Community
News
Book
Government
Document
———————-
Expression
Arts
Poem
OEDILF: The Omnificent English Dictionary In Limerick Form
More News …
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
- Rover findings offer glimpse of Red Planet's...on September 29, 2022 at 4:20 pm
CU Boulder geologist Lisa Mayhew is among the scientists working to recreate the history of an ancient landscape that wouldn't look out of place in Utah—only this terrain sits on Mars millions of miles from Earth.
- From super-sealings to the detection of dangerous...on September 29, 2022 at 3:56 pm
When accelerated neutrons or ions bombard a material, its surface layer undergoes dramatic physical and chemical transformations. The National Center for Nuclear Research in Swierk, Poland, has managed to learn in detail about the processes occurring in such situations in polymers. The collected knowledge was used by physicists to create a method of producing super-sealings, they also proposed a simple and quick way to detect dangerous cables whose polymer insulation begins to lose their […]
- Study hints at how fishes in the twilight zone...on September 29, 2022 at 1:21 pm
A new study, led by British Antarctic Survey and the University of Bristol, provides the first evidence that a controversial evolutionary process may be responsible for lanternfishes becoming one of the most diverse families of fish in the deep sea.
- Receding ice leaves Canada's polar bears at...on September 29, 2022 at 8:18 am
Sprawled on rocky ground far from sea ice, a lone Canadian polar bear sits under a dazzling sun, his white fur utterly useless as camouflage.
- Researchers design treatment to protect bones...on September 26, 2022 at 7:23 pm
University of Central Florida material sciences engineers Melanie Coathup and Sudipta Seal have designed a cerium oxide nanoparticle—an artificial enzyme—that protects bones against damage from radiation. The nanoparticle has also shown abilities to improve bone regeneration, reduce loss of blood cells and help kill cancer cells.
——–
Related
Here are links to pages about closely related subjects.
Sphere Land, Ice, Water (Ocean), Air
Ecosystem Forest, Grassland, Desert, Arctic, Aquatic
Life Cell, Gene, Tree of Life
Microorganism
Plant Flower, Tree
Animal
Invertebrate Cuttlefish, Octopus, Ant, Bee, Butterfly, Spider, Lobster
Vertebrate Fish, Seahorse, Ray, Shark, Frog, Turtle, Tortoise, Dinosaur
Bird, Ostrich, Owl, Crow, Parrot
Mammal Bat, Rabbit, Giraffe, Camel, Horse, Elephant, Mammoth
Whale, Dolphin, Walrus, Seal, Polar Bear, Bear, Cat, Tiger, Lion, Dog, Wolf
Monkey, Chimpanzee, Human
——
Notes
1. The resources on this page are are organized by a classification scheme developed exclusively for Cosma.