The Seals: Characteristics, habitats, main types, threats and more

We invite you to know all about the seals, phocids or Phocidae in scientific terms. These animals belong to the marine pinniped mammal family, which also includes walruses, and sea lions and sea bears.

Physical Characteristics

To date, 19 species of seals have been established, which inhabit coastal areas of low temperatures. In terms of weight and height, these characteristics vary depending on the species: while a southern elephant seal can reach up to 4.5 meters in length and weigh even 4000 kilograms, a ringed seal barely reaches 1.6 meters in length and a weight not greater than 100 kilograms. 

A distinctive feature of the seals is the arrangement of their hind limbs, since being slightly tilted back; they facilitate locomotion in water but make it difficult on land.

Additionally, these creatures lack  auditory pavilions, but they do have interesting internal adaptations in their body, such as their dense layer of subcutaneous fat, which allows them to combat the intense cold.

Habitat and Distribution

Seals have a widespread distribution, as they can be found from the cold regions of Antarctica to very warm areas with abundant sunshine, although most are in Antarctica, where there is an extreme cold. In the case of the terrestrial sphere, the pole located at the north end is called north, boreal or Arctic pole and to the one located on the South pole, Southern or Antarctic.

We invite you to continue reading this article, to learn more about the specific distribution according to each seal species.

What Do  Seals Feed On?

The seals are aquatic mammals that have a thick layer of fat which allows them not only to face the harsh temperature conditions in their environment, but to dive in the water up to 600 meters. Thanks to this condition, they can feed on shellfish, fish and cephalopods that inhabit the seabed, although penguins, and even other smaller seals, also integrate their menu.

In addition, their strong molar teeth allow them to crush the shells of certain mollusks. The huge ability of the seals to hunt and search for food is also based on their huge whiskers.

These structures are capable of detecting small vibrations in the water, produced by the displacement of fish. Even in low-light environments or zero visibility, seals are able to determine the location of the fish through their whiskers. An adult seal can ingest about 5.5 kilograms of food a day, representing 5% of its body weight.

seals : pups diving and hunting

Main Types Of Seals:

There are around 19 seals species, and we are listing the most important following.

Southern Elephant Seal:

This creature is one of the two species of sea elephants, being the Mirounga angustirostris or Northern elephant Seal the other member. It’s  also the largest member of the Pinniped genus, as well as the largest marine mammal that is not a cetacean.

They are named because of their large size and the males’ large trunk , which resembles the trunk of an elephant, which he uses to produce very noisy roars, especially during the breeding Season.

This species is approximately 40% heavier than the northern elephant seal and twice as heavy as a male walrus.  The male once adult, has measures of more than 4.5 meters of total length, in the same way reaches a weight between 2200 and 4000 Kilograms. As for females they measure about 3.5 meters in length and an average of 900 kilograms of weight.

Habitat and Distribution

The southern elephant seals inhabit the open ocean during the non-reproductive period, where they can be immersed in notable depths. During the breeding season, they are usually found on rocky beaches and terrain, and sometimes on ice and snow.

As for their distribution, it should be noted that this species has a population of about 675 000 individuals distributed mainly in the areas that make up the border of the Antarctic Continent. (we invite you to read our article Southern Elephant seals to learn more about these creatures.)

the seals : southern elephant seals male and female

Bearded Seals

This species is characterized by its large body, which has a fairly rectangular shape and its head looks small compared to the rest of its anatomy.  Its frontal fins have square shape and strong claws, with the middle finger being the longest.

But its most distinctive aspect lies in its thick whisker which tend to curl when dried and is the main responsible of its name.

As for their color, adult individuals have gray and dark shades, even brown in in some occasions, with the dorsal part of these seals concentrating the darker shades.

In some cases there are also spots located on their backs or a series of dots or moles of dark tones on their flanks. Adult specimens measure between 2 and 2.5 meters long.

As for its weight this varies drastically in each annual cycle, but the average is 250-300 kg. However, females of this species are slightly larger than males, and can reach an overweight of 425 kilograms during the spring.

Habitat and Distribution

Bearded seals are distributed throughout the Arctic Circle. Their preferred habitats are ice blocks and icebergs located on shallow water surfaces.

During their teenage years they usually roam through fairly broad routes, but in their adulthood they change this behavior as they stay close to their habitat in coastal waters most of the year. We invite you to read our article bearded seals to learn more about them.

Weddell Seals

This is some kind of big seal. Males measure from 2.5 to 2.9 meters long and females reach 3.5 meters. They weigh between 400 and 600 kg. As for their fur, adults have nuances that vary between dark grey and light grey with a kind of moles or darker areas, in the form of spots.

In the first moments of their lives, these beautiful mammals have lighter nuances, which change until they darken when they grow. As for their head, it is small in relation to the size of the body and its color is usually mottled gray and black on the back. The body of the Weddell seals adapts perfectly to the cold temperature, as their organs are covered by thick layers of fat.

Habitat and Distribution

These creatures have a circumpolar distribution and are coastal, staying all the time on icebergs and venturing only up to 15 to 20 km in the Antarctic Ocean to eat. They are usually easy to find in the small islands located in these areas, although there is also a record of Weddell seals on the ice-free islands on the Antarctic Peninsula. We invite you to read our article Weddell seals to learn more about this species.

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Ringed Seals

The ringed seals are small seals which can be found in a range of colors ranging from silvery grey to brown. On the other hand, their abdomens have bright shades while their backs are dark with striking rings that are the main reason for their names.

Adult specimens measure between 1 and 1.6 meters and weigh between 50 and 100 kilograms. In the same way as other Nordic seal species, their body mass varies in big proportion depending on the time of year. 

These creatures tend to gain weight in the fall, while in late spring and early summer they lose weight and look thinner. Males are slightly larger than females, and during spring their faces look much darker due to a secretion of oil from the glands of the facial region.

Habitat and Distribution

This species is the most abundant in the Arctic region and although it is difficult to calculate its population, it is thought that the number of this species exceeds 5 million specimens. Sea ice is the only habitat of this species, and that is where they mate, molt their skin and rest.

They seldom rise to the surface and create holes in the ice, using the claws developed from their front fins.Ringed seals are distributed throughout the Arctic.

It is the only kind of polar seal that can breathe in the holes of the frozen sea, and this special ability allows them to have an extensive distribution in the Arctic and Subarctic. We invite you to read our article ringed seals to learn more about these creatures.

Hooded Seals

These seals have a black face and a greyish-blue skin with dark spots.  However, the main reason for their name is based on the amazing nasal appendage that adorns the head of adult males which develop at around 4 years of age.

The wide, fleshy snouts lean over their mouth, but when they are inflated, they form a flashy «bulbous hood» on the top of the head, that gives them a spherical appearance due to their oval shape.

Males also have an inflatable nasal membrane that expands like a red balloon when they shake.

This species has sexual dimorphism since females have smaller measures than males. The adult male measures about 2.6 meters on average, although cases of specimens of up to 3.5 meters of length have been reported.

In turn, adult females have an average length of about 2 Meters.  As for weight, males weigh about 300 kilograms on average, while females only reach about 160 kilograms.

Habitat and distribution

This is a migratory species with a range that covers a large part of the North Atlantic. The annual movement of hooded seals usually follows the movement of Ice blocks.

There are four main breeding areas including: Gulf of San Lorenzo; an area at the north of Newfoundland known as the Front; The Davis strait; and West Ice, east of Greenland. Outside the breeding season, it is not uncommon for hooded seals to be observed outside their normal range, and juveniles even reach Portugal, Florida, and even California in the Pacific. We invite you to read our article hooded seals to learn more about these creatures.

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Harp Seals:

Harp seals have sharp, pointed snouts, small pectoral fins with claws and small hind fins. Like other species of similar seals, they have beaded whiskers on their snouts.

Their bodies can be described as moderately plump with a small, slightly pointed head and a moderately thick neck. Their snouts are relatively short and their eyes moderately large.

Harp seals present a slight sexual dimorphism in size and Fur. Males weigh an average of 135 kg and have a length of 171 to 190 cm. Females weigh an average of 120 kg and measure between 168 and 183 cm long.

In addition to being larger than females, male harp seals usually have a more defined «harp» pattern and their heads are blacker than females.

In addition, their heads are flat and wide, and tend to have a rather long but sharp snout.

Habitat and distribution

The largest known population of harp seals inhabits the Atlantic, specifically in the northern Western region, just east of Canada.  In turn, this population is divided into smaller distribution groups; one of them inhabits the coast that corresponds to the peninsula of the Labrador and part of the island of Newfoundland.

On the other hand, the other known subgroup of the Atlantic Zone lives in the vicinity of the Magdalena islands, specifically in the Gulf of San Lorenzo. All these data correspond to the largest populations of harp seals. We invite you to read our article harp seals to keep learning about them.

Crabeater Seals

These adorable creatures, along with Ross seals, Leopard seals and Weddell seals, make up the group of Lobodontine seals which are characterized by having adaptations in their teeth including the lobes and cusps, which are useful for removing small prey from the water (the name  «Lobodontini «, meaning «tooth lobe «).

The crabeater seal is the most abundant seal species on earth, and it is believed that its population is even bigger than the total population of the rest of the seals as a whole. Despite their names, they do not feed on crabs, but on krill (shrimp-like crustaceans).

As for its anatomy, the adult specimens are relatively thin and pale, with an average length of 2.5 m and a weight of 200 kg. However, it is good to emphasize that females are a little larger. The skulls and snouts of the Crabeater seals are longer than those of other Antarctic seals, and give their faces a dog-like appearance.

Their teeth are very different and are considered the most complex among all mammal species.The color of their skin fluctuates throughout the year, depending on the Moult. After that, their backs are brown or dark gray in some cases and their bellies are of a blond or pale color.

Habitat and Distribution

Antarctica is the most common habitat of these seals. The data indicate that their population has been distributed in this area for about 15 to 25 million years. However, they are also found in some areas of South America, parts of Australia and in turn in New Zealand, in a smaller proportion. We invite you to read our article Crabeater seals to learn more about these Creatures.)

Leopard Seals

These seals are characterized by being large and very voluptuous in terms of muscles, and their skin color may vary but are mostly dark gray on the top of their body, while their abdomen is light gray with dark or black spots that resemble the dots that the leopards have.

Their head and snout are a little small, although they have a relatively long neck. Contrary to other types of seals, Leopard seals have relatively large fins that give them a better mobility to move overland and swim comfortably when they need to capture their prey.

Females of this species measure between 3.5 and 4 meters in length and their weight ranges between 500 and 600 kilograms. In turn the length of males varies from 3 to 3.8 meters, while their weight is approximately 320 kilograms.

Habitat and Distribution

The Leopard seal habitat focuses primarily on the cold seas of the Antarctic Ocean, and the mountainous areas and large blocks of ice that surround them commonly serve as their home. However, they spend most of their time in the water or resting on large blocks of ice.

Today, it’s estimated that the total population of leopard seals is about 220,000 individuals, so despite the consequences of climate change, this species is not yet considered extinct. They develop migratory patterns, especially when they are in their juvenile stage, being common to find them in the Falkland Islands, the Cook Islands and South Africa, which are far from their natural habitats. We invite you to read our article Leopard Seals to learn more about them

Mediterranean Monk Seals

This is the most endangered seal species, and there are actually only 600 specimens in the world. They are characterized by having a body with a rounded head and short limbs, with small fingernails.

In addition, their body is very robust though small and their hair is very dark, usually brown or gray on the back and light or white shadows on the abdomen.

Males tend to have a darker fur than females, so they are sa

Id to have a slight sexual dimorphism.

However, the color usually varies in the same individual with age. Adult specimens can reach between 2 and 2.8 meters in total length and weigh between 240 and 300 kg.

Habitat and distribution

At the eastern Mediterranean is where the largest populations of these seals are found, especially at the islands of the Ionian Sea and the Aegean Sea, as well as on the shores of Turkey, Albania, Croatia and Greece.

In the Western Mediterranean, they can be found in

Algeria and MOROCCO, and in the North Atlantic in Cape Blanco between Mauritania and Western Sahara and also in Madeira. Their habitat includes pelagic zones, small islands and coastal areas, but always in protected areas from the access from their terrestrial predators. We invite you to read our article Mediterranean Monk seals to learn more about these Creatures.


Are the Seals Endangered?

Among their natural threats the seals have different predators such as polar bears, orcas, sharks and even leopard seals, especially for specimens that are in their juvenile stage.

Another major threat for the seals in general is given by the global warming, which is destroying their habitat and which is important to learn about. This phenomenon is based on the rise in the temperature of the oceans and the Earth’s atmosphere, caused by the massive emissions that enhance the greenhouse effect.  This phenomenon occurs when certain gases from the earth’s atmosphere retain the Heat. These gases let the light through but keep the heat like the glass walls of a greenhouse.

First, sunlight shines on the Earth’s surface, where it is absorbed and then returns to the atmosphere in the form of heat.

In the atmosphere, greenhouse gases retain some of this heat and the rest escape to the space. The more greenhouse gases, the more heat is retained.The main greenhouse gases emitted by human beings are carbon dioxide or CO 2) and methane (CH 4).

As a result of this phenomenon the glaciers have melted, the sea level has increased, the forests have dried up and the fauna and flora have been significantly affected.  We humans have caused most of the global warming by issuing heat-retaining gases to enhance our modern life.

The rapid increase in greenhouse gases is a problem because it’s  changing the climate so fast, that some living beings just cannot adapt. Similarly, a new and more unpredictable climate imposes unique challenges for all kinds of life.

What measures can we take to collaborate?

Reduce emissions: use less the private car, as long as you can, use sustainable means of transport, such as bicycle, or use more public transportation. For long distances, the most sustainable transportation mean is the train, above the plane, which causes much of the CO2 emissions emitted into the atmosphere.

Save energy: look at the labels on the appliances, and never leave them in standby. Always adjust the thermostat for both heating and air conditioning. Taking care of the use of home appliances a little, we can save Energy.

Put into practice the 3 ‘ R’s of sustainability

Reduce: consume less, more efficiently.

Reuse: Take advantage of second hand markets, to give another chance to what you no longer use or to get something you need and that someone else has discarded. You will save money and reduce consumption.

Recycles: paper, aluminum or plastic and electronic waste, etc. You can save more than 730 kilograms of CO2 a year only by recycling half of the garbage that is generated in your house.

Act against forest loss :To the extent that you can, avoid what causes fire risks. – If you want to buy wood, bet on that with certification or seal that ensures its sustainable origin.

Plant a tree! In all its life, it can absorb up to one ton of CO2.

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