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What Are Some Different Types of Seals?

Jessica Ellis
Jessica Ellis
Jessica Ellis
Jessica Ellis

The seal, also called the true or earless seal, is one of three groups that make up the pinniped family. The seal family, Phocidae, is comprised of at least 18 living species and 20 extinct varieties. They are all aquatic mammals and inhabit oceans around the globe, from tropical waters to Antarctic seas.

The crabeater Pacific Harbor seals of Antarctica are believed to be the second most populous mammal on the earth, after human beings. They are also one of the fastest seals alive today, able to achieve swimming speeds of up to 16 miles per hour (25 kph.) Although the exact population of this species is unknown, the most recent estimates suggest somewhere between 8-50 million individual animals exist. Despite their name, the crabeater does not eat crabs, existing on a diet of krill.

Antarctica is home to the crabeater seals, one of the world's most populous mammals.
Antarctica is home to the crabeater seals, one of the world's most populous mammals.

Another Antarctic pinniped is the fearsome leopard seal, an apex predator of the reason. Leopard seals are large, weighing up to 705 lb (320 kg) and reaching lengths of up to 9.2 ft (2.8 m.) This species dines on penguins, and has even been known to stalk humans in the area. The leopard seal has appeared as a villain in several recent movies, including Happy Feet, and Eight Below.

Experts believe that the Hawaiian monk seal is one of the oldest forms of seals still alive, existing for perhaps 15 million years. In earlier times, this seal was relentlessly hunted for its pelt, driving the population to dangerously low levels. Despite protection from the US Endangered Species Act, there are only 1,200 of these animals left in the world. Monk varieties of seal have been driven to near extinction around the globe. The Mediterranean monk seal is even rarer than the Hawaiian, and the Caribbean monk seal has been extinct since the 1950s.

Northern and Southern elephant seals are among the largest seal species alive today. Named for the trunk-like protrusion on their faces, bull males can reach 8,000 lbs (3636 kg) and 21 ft (6.3) in length. Despite the near extinction of both varieties during the 19th century, populations have steadily grown since the passing of various protection laws in the 20th century. Both types of elephant seal are noted for their fierce battles during the breeding season, and bark so loudly they may be heard across large distances. During mating season, they populate in enormous numbers along the beaches of their home ranges.

The harp seal is an Arctic species, and is heavily sought after by fur traders for its coat. Pups are particularly sought out by hunters, as the animal is unable to swim, run, or dodge attacks, and their coat is quite valuable during the first few months. Harp seal hunting is typically done by hitting the animal over the head with a large club. Despite large protests by animal activists, in 2006 the Canadian government increased the three-year quota of seal kills to 975,000. Data for the 2006 hunt shows that 325,000 harp seals were slaughtered.

While some seal species are doing well in terms of population, others are considered vulnerable or endangered by the International Union for the Conservation of Nature (IUCN.) If you wish to help conservation efforts for seals, many reputable organizations exist that would be appreciative of your volunteer hours or donations. If you object to the hunting of seals for fur, you may wish to aid anti-seal hunt organizations or refuse your business to stores where fur products are sold.

Frequently Asked Questions

What are the most common types of seals found worldwide?

Among the most common seal species are the Harbor Seal, known for its widespread presence along temperate and Arctic marine coastlines, and the Grey Seal, often spotted in the North Atlantic. The Harp Seal, with its distinctive black face mask, is also prevalent, particularly in the Arctic and North Atlantic regions. The Leopard Seal, notorious for its top predator status in Antarctic waters, and the Elephant Seal, remarkable for its massive size and pronounced sexual dimorphism, are also well-known. Lastly, the Weddell Seal, a resident of the Antarctic ice shelves, is recognized for its ability to thrive in extreme cold.

How do seals differ from sea lions?

Seals and sea lions are both pinnipeds, but they belong to different families. Seals, or true seals, are part of the Phocidae family and are characterized by their lack of external ear flaps, shorter flippers, and the way they move on land by wriggling on their bellies. In contrast, sea lions, from the Otariidae family, have visible ear flaps, longer flippers, and can walk on land using their flippers. Sea lions are also generally more vocal and social than true seals.

What adaptations do seals have for living in cold environments?

Seals are well-adapted to cold environments with several physiological and behavioral traits. They have a thick layer of blubber that insulates their bodies and stores energy. Their fur provides additional insulation, and their circulatory system can adjust to conserve heat. Seals also have the ability to slow their heart rate to reduce oxygen consumption during long dives in frigid waters, which is crucial for hunting and survival in icy habitats.

Are seals at risk from climate change and human activities?

Yes, seals are increasingly at risk due to climate change and human activities. Melting ice habitats, particularly in the Arctic and Antarctic, directly threaten species like the Harp and Weddell seals that rely on ice for breeding and resting. Additionally, seals face threats from overfishing, which depletes their food sources, and from entanglement in fishing gear. Pollution and shipping traffic also contribute to habitat degradation and increased mortality rates.

What is the largest species of seal, and where can it be found?

The Southern Elephant Seal holds the title for the largest seal species. Males can grow up to 20 feet in length and weigh over 8,800 pounds. These colossal seals are found in the Southern Hemisphere, with breeding colonies located on sub-Antarctic islands. The largest populations are found on South Georgia, the South Shetland Islands, and Macquarie Island.

How do seals contribute to their ecosystem?

Seals play a vital role in their marine ecosystems as both predators and prey. As predators, they help maintain the balance of fish and invertebrate populations. Their foraging habits can also influence the distribution and behavior of their prey. As prey, seals provide sustenance for larger predators, such as orcas and polar bears. Furthermore, their nutrient-rich feces contribute to the ocean nutrient cycle, supporting plankton growth and overall marine productivity.

Jessica Ellis
Jessica Ellis

With a B.A. in theater from UCLA and a graduate degree in screenwriting from the American Film Institute, Jessica is passionate about drama and film. She has many other interests, and enjoys learning and writing about a wide range of topics in her role as a AllThingsNature writer.

Learn more...
Jessica Ellis
Jessica Ellis

With a B.A. in theater from UCLA and a graduate degree in screenwriting from the American Film Institute, Jessica is passionate about drama and film. She has many other interests, and enjoys learning and writing about a wide range of topics in her role as a AllThingsNature writer.

Learn more...

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    • Antarctica is home to the crabeater seals, one of the world's most populous mammals.
      By: axily
      Antarctica is home to the crabeater seals, one of the world's most populous mammals.