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What is a Seal?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

The term “seal” is often used to refer generally to pinnipeds, members of a superfamily of mammals by the same name. It is also used specifically to refer to the so-called “true seals” in the family Phocidae. The defining characteristic of a seal is that it is a mammal with flippers, adapted to an aquatic life, and capable of survival both in and outside of the water, unlike dolphins, another group of flippered mammal which you may be familiar with.

All pinnipeds have sleek, muscular bodies which are designed for swimming, and they are also carnivorous. Many have powerful teeth and jaws adapted to make them formidable hunters, and they are also extremely fast, powerful swimmers, able to pursue prey across extended distances. A seal is also capable of remaining underwater for up to two hours without needing fresh air, thanks to the amazing oxygen conservation abilities of pinnipeds.

Like seals, the walrus is considered a pinniped.
Like seals, the walrus is considered a pinniped.

True seals spend most of their life in the water, and they tend to be very awkward on land. They communicate by grunting and slapping the water, and their rear flippers are more developed than their fore flippers. In the water, true seals move very sinuously, revealing themselves as animals well used to the marine environment. Eared seals, on the other hand, have more developed front flippers, and they are comfortable navigating on land as well as in the water. They are also very vocal; sea lions are one example of eared seals.

The walrus is also considered a pinniped. Walruses are distinguished by their massive bodies and formidable tusks, and they are particularly fond of shellfish. The walrus was once a widespread pinniped, but it is not restricted primarily to the arctic regions of the world. Walruses also have a very unique feeding technique which allows them to crush shells in their mouths, suck out the usable flesh inside, and spit out the remainder, almost like they are vacuuming out the shell.

When you see a performing seal, you are actually looking at a sea lion, a member of the eared seal group. True seals cannot perform the tricks associated with seals in zoos and circuses, as they lack the large front flippers needed to navigate with confidence on land. The seals along the seashore are also not true seals, as you can tell by their vocalizations and well developed front flippers.

Frequently Asked Questions

What exactly is a seal?

A seal is a marine mammal belonging to the order Pinnipedia, which means "fin-footed." Seals are adapted to life in the water with their streamlined bodies, flippers for swimming, and blubber for insulation. They are divided into two families: Phocidae (true seals or earless seals) and Otariidae (eared seals, including sea lions and fur seals).

How do seals differ from sea lions?

Seals and sea lions are both pinnipeds, but they have distinct differences. Seals (Phocidae) lack external ear flaps and have shorter flippers, which makes them more agile in water but less mobile on land. Sea lions (Otariidae), on the other hand, have visible ear flaps and larger, stronger flippers that allow them to "walk" on land.

What do seals typically eat?

Seals are carnivorous and primarily feed on fish, squid, shellfish, and crustaceans. Their diet can vary widely depending on their species and habitat. Some seals, like the leopard seal, are known to be apex predators and may also hunt other seals or penguins.

Where can seals be found in the world?

Seals are found in a variety of marine environments across the globe, from the frigid Arctic and Antarctic regions to tropical climates. They are highly adaptable and can live in both coastal and open ocean waters. Some species, like the harbor seal, are commonly found along temperate and subarctic coastlines.

How do seals adapt to cold water environments?

Seals are well-adapted to cold water environments thanks to their thick layer of blubber, which provides insulation and energy reserves. Their fur also offers additional warmth, and their circulatory system can adjust to conserve heat. Moreover, seals can slow their heart rate to reduce oxygen consumption during deep dives.

Are seals endangered?

The conservation status of seals varies by species. While some, like the ringed seal, are classified as Least Concern by the IUCN, others face threats from climate change, habitat loss, and hunting, leading to vulnerable statuses. The Mediterranean monk seal, for example, is one of the world's most endangered marine mammals.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a AllThingsNature researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a AllThingsNature researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

anon192356

I need to find some more information about seals for a report that I'm doing in school. Anyone have any additional information that I could use? i am apaika.

CellMania

@christym: The seal’s long whiskers help them to detect vibrations while they are underwater. They can close their nostrils while swimming.

Seals have only breeding cycle per year and they have what is called delayed implantation. That means that the embryo is dormant for 2 to 3 months before it implants and continues to develop.

Seals have more blood for their body size than any other land animal. A group of seals is called a pod or a herd.

GardenTurtle

@christym: Seals are very fascinating creatures. My colleagues and I had the opportunity to visit the Sea Lab in Dauphin Island and learned a lot about our aquatic friends.

Male gray seals can grow up to ten feet long and the females are between seven to seven and a half feet. Male seals are also darker in color than the females. The average lifespan of a seal is between 30 and 40 years.

Seals mate on ice or land. There are 18 different species of seals. The largest seal is the Elephant seal, weighing in at around 5,000 pounds. A seal’s milk is high in fat (40% to 50%), so their babies quickly grow and gain weight.

christym

I need to find some more information about seals for a report that I'm doing in school. Anyone have any additional information that I could use?

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    • Like seals, the walrus is considered a pinniped.
      By: MAK
      Like seals, the walrus is considered a pinniped.