Seal family. Interesting features of seals

• KEY FACTS
• Name: Gray (long-faced) seal (Halichoerus grypus); the spotted seal (Phoca vitulina vitulina) and the Baltic ringed seal (Phoca hispida botnica).
• Area: Baltic Sea
• Size of social group: True social groups No; most species typically form breeding groups of hundreds or thousands of individuals
• Gestation period: 6-11 months (depending on the species), including the latent stage period
• Number of cubs: One
• Gaining independence: 2-4 weeks

Seals belong to the order Pinnipedia, which means “pinnipeds.” Large flippers allow them to swim well, but on land, seals move rather clumsily.

Pinnipeds live primarily in water, and most of them come to land only during the breeding and molting season. There are about 30 species of these animals in three families of pinnipeds. In this article we will focus on public behavior pinnipeds of the family Phocidae, called earless or true seals. We will also look at the lifestyle of native species Baltic Sea, among which is the northern elephant seal (Mirounga angustirostris).

Social behavior elephant seal, whose males fight each other for control of a group of females called a harem, has been extensively studied by zoologists. During the year, elephant seals usually lead a solitary lifestyle and only periodically go out on land or ice in groups. Even the mother does not take proper care of her offspring. She rarely teaches them the skills needed to adult life, feeds newborn cubs with milk for only a few weeks and leaves them to their fate.

A crabeater seal rests on ice in Antarctica. Representatives of this species feed on plankton, capturing it with their open mouth while swimming and filtering it sea ​​water through the teeth.

Baltic seals

Three species live in the Baltic Sea: the seal, or gray (long-faced) seal; the larga, or spotted seal, and the Baltic ringed seal. For most of the year they all lead a solitary lifestyle.

In order to give birth to future generations, seals must go onto land or dense ice, because if a calf is born in water, it will immediately drown. However, seals also leave the water during molting. Having changed their habitat, they gather in groups, and during this period not a trace remains of their hermit lifestyle. If the seals' skin is warm, they grow new fur. On land, animals move very slowly, so they form mass aggregations on land to protect themselves from predators.

All Baltic seals leave the water in spring or early summer and gather in traditional places breeding on ice fields. In females that have been well fed during 8-9 months of pregnancy, cubs appear soon after entering the ice. Mothers need a solid supply of fat (i.e. subcutaneous fat), which provides them with vital energy while nursing their babies, since during this period females rarely have time to eat. Female gray and spotted seal pups are born on open ice near the recesses that their mothers dig and clean in advance. In contrast, female ringed seals dig caves in the snow more than 2 m deep - the so-called. haulouts, which can consist of several compartments.

Northern fur seals spend 6-8 months a year in the open sea and come to rocky land only in the summer, during the breeding season. The picture shows a colony of fur seals in Alaska (USA).

Offspring

Newborn babies of all three species (they are also called puppies) are born in a white fluffy coat. A spotted seal baby usually molts in the womb and is born in a gray “baby” coat, but newborn gray seal and ringed seal pups are white and fluffy. Gray seals shed their white fur after three weeks, while ringed seals shed their white fur at 4-6 weeks of age.

Spotted seal pups are larger and generally better developed than those of other species. They are able to crawl and swim within a few hours after birth. This early development favorable for a species that spends up to 75% of its life in water.

The gray seal takes less care of its cubs than other relatives. The female feeds the babies with milk for only 14-17 days, and then they are left alone with all the dangers of life. Seal milk is very fatty, and during the feeding period the pups gain up to 2 kg per day. The resulting stock subcutaneous fat The puppy is very necessary, because when the mother stops feeding him, he will not be able to eat until he gets to the water.

Usually after two weeks, hungry puppies begin to master the water element. Babies get food on a whim, they are not helped by relatives, but often young animals follow adults to find good feeding places.

Female spotted seals and ringed seals pay more attention to their babies. The period of feeding the offspring lasts 4 and 6 weeks, respectively, during which time they themselves sometimes manage to eat. The young of both species can swim from the very beginning. early age and sometimes accompany their mothers in search of food. This allows children to learn the basics of future independent life.

Rival males

When the females stop nursing their pups, mating season begins for all seal species. Males compete for the location of females, and male gray seals also compete for territory in breeding areas; they mate with all females that come to their territory.

Signs of the beginning of a conflict between two seals are the men's menacingly open mouths, loud cries and display of sharp teeth. During the fight, males may bite each other's neck and front flippers or press each other to the ice. During the mating season, winning males can woo more than ten female friends. However, such an advantage must first be won. It happens that males successfully defend their territory only after reaching 10 years of age.

Male spotted seals have a different strategy. At a certain point, they gather in areas popular with females and put on a “water acrobatics show” accompanied by underwater sounds. Females give preference to those males whose performance impressed them the most. The mating rituals of ringed seals are not well understood, but it is believed that males defend underwater territories where mating occurs.

Pacific coast in California (USA). The photo captures the fight between two northern elephant seals during mating season. Before the fight, the animals open their mouths wide, bare their teeth and scream loudly.

Males of all species do not eat anything during the mating season and sometimes lose up to 25% of their weight. After the mating season is over, adult seals - both males and females - leave the ice fields and regain lost strength within a few weeks. During the rest period, they prepare for the upcoming molt, when they will have to leave the water and exist for some time without food.

Northern elephant seal

Elephant seals are the largest of the pinnipeds. They got their name from the male's short trunk, which hangs over his jaw and becomes larger during conflicts over territory. There are two species of elephant seals: the southern elephant seal and the northern elephant seal.

Like most pinnipeds, the northern elephant seal comes to land only during the molting and breeding periods. Males arrive at the “mating territory” in early December and compete for the right to occupy it. The winner will receive the favor of all the females who come to his territory, which is why males fight so fiercely for the best territory. In battles in which a clearly larger and more dominant male is involved, the weaker one usually concedes, and if the strength of the males is equal, the battle lasts until one of them wins. When approaching each other, the males rear up, reaching 2-3 m in height, inflate their trunks and roar loudly. If none of the rivals gives up, the seals make swift attacks and injure each other with sharp teeth. Most of them have many scars from such battles. Sometimes battles between northern elephant seals can result in the death of one of them.

2-3 weeks after the arrival of males, females arrive at the breeding sites, ready to give birth to babies. They choose areas with best conditions, forming harems. Females give birth to one calf 6-7 days after arrival and feed it with milk for about 28 days. During this period, the male - the owner of the territory - guards the harem. IN last days After feeding, males mate with females again.

The Hard Life of the Cubs

Like other harem-forming animals, male northern elephant seals are significantly larger than females. Their dimensions pose a danger not only to females, but also to babies. Every seventh puppy dies because it was crushed by a male who simply did not notice the cub.

Strange females also pose a threat to babies. If the puppy loses contact with its mother, it will join another female to feed on her milk. However, most often the alien female does not allow this. Like other seals, she does not eat anything during the mating season, and milk is produced from the reserve of subcutaneous fat. The female takes care of this valuable product only for your baby, because the chances of his survival in the future depend on the fat reserves that he will have time to accumulate during the period of breastfeeding. If someone else's cub is too persistent in demanding milk from the female, she may expel him or even kill him. Only occasionally does a mother who has lost her cub share her milk with orphans, but the cubs she feeds rarely survive.

The dominant male usually takes care of a harem of 40 females. The larger the territory that the females occupy, the more difficult it is for the male to defend his right to them. Fierce competition between males means that only a third of them have the opportunity to mate. Almost 90% of the young in a large colony are usually fathered by only a few successful males.

Although the lifespan of seals can be over 15 years, the dangers associated with protecting the territory and harem, as well as the loss of more than a third of their weight during the mating season, mean that males rarely have the strength to participate in reproduction for more than 3-4 years. Most males die after two successful mating seasons.

Male scammers

Many males are not large or strong enough to fight for territory, which means they have no chance of mating. But not all of them are ready to accept this state of affairs - some are trying to be cunning using alternative methods. Zoologists call such males “thieves.” Some thieves, at the end of the mating season, wait for females who return to the sea, and, seizing the moment when the dominant male ceases to guard the harem, mate with them. This tactic occasionally bears fruit, but often they fail to win the favor of females, because... most of them are already pregnant by that time.

Other thieving males wait for the opportunity to challenge the dominant male when his strength is running low after active struggle with rivals. Still others, most often underdeveloped males who are more similar to females, may try to penetrate the harem in the hope that the dominant male will not notice them and try to mate with the females. However, it is undesirable for females to show their affection to such males, since their offspring may turn out to be weak. Most often in such a situation, females scream, attracting the attention of the dominant male, who comes to the rescue and drives away the uninvited guest. Thus, females select only the strongest males as fathers of their offspring.

Eared and real:

Everything about the seals of our planet

How to distinguish a gray seal from a ringed seal? After all, many people still confuse them. It would not be a crime to call a seal a seal, but experts do not recommend calling a seal a seal. And yet, only a small part of the animals with flippers that inhabit the seas, lakes and oceans of our planet are represented in the Baltic region. We tell you why the name “pinnipeds” does not exist, how eared seals differ from real ones, and how many seals live in Russia.

Pinnipeds are obsolete! Of course, out of habit, we all call animals with flippers instead of paws pinnipeds - fur seals, gray seals, and even walruses. However, scientists have long excluded this detachment from modern classification. By modern ideas, these animals have different ancestors.

Eared seals and walruses are closest to bears - this is where they get their small heads, hard brown fur, and small ears. It is believed that these animals went into the water in Pacific Ocean, although the earliest remains of an eared seal were found in France, in the Atlantic basin.

And the closest relatives of true seals are mustelids. This is where the elongated spindle-shaped body and short limbs relative to the body come from. For the first time, real seals entered the water in the North Atlantic Ocean.

The flippers of true and eared seals, as well as of walruses, developed in parallel - in an evolutionary way: after all, the paws of animals that hunt in water are not very comfortable. It is in the structure of the flippers that eared seals differ from real seals. The latter cannot stand on their hind flippers, and when moving on land they simply drag behind them. But Steller sea lions - this is also the name of the long-eared family - calmly walk along the shore with their flippers: their hind limbs are bent forward at the heel joint and look like a flattened leg!

Where do seals live? In the Northern Hemisphere, eared seals live only in the Pacific Ocean. And in the South - they are found at the southern tip of the South American continent in the Atlantic Ocean, as well as off the southwestern coast of Australia in Indian Ocean. Walruses live only in Northern Arctic Ocean and the adjacent basins of the Pacific and Atlantic oceans - in general, around the North Pole.

Real seals also prefer colder waters - in the subpolar or temperate latitudes. The only exception is the tropical monk seal. Subspecies of this animal inhabit the Black Sea and the Pacific Ocean near the Hawaiian Islands.

There are also three species of freshwater seals in the world, and two of them live in Russia. These are the Baikal seal and the Ladoga subspecies of the ringed seal. The third freshwater seal is the Saimaa ringed seal, the only endemic mammal in Finland. According to experts, the resettlement into fresh waters occurred accidentally, and is associated with the retreat of glaciers. Previously, seals inhabited the seas, but when the glacier left, they found themselves isolated in inland waters. And adapted to fresh water. By the way, experts say that only Baikal seal. And the Saimaa and Ladoga seals are just freshwater subspecies of harbor seals.

What types of seals are there? The family of eared seals includes 7 genera and, according to different classifications, 14 or 15 species. Only two species live in Russia - sea lion, or northern sea ​​lion, and northern fur seal. Both species are listed in both the Russian and International Red Books. The sea lion is considered endangered and the northern fur seal is considered vulnerable according to the IUCN classification.

Seals, sea lions and walruses are oceanic mammals in the group Pinnipeds (Seals). Seals' connection with water is not as close as that of whales. Seals require mandatory rest on land.

Seals are related, but are in different taxonomic families.

• The so-called earless (true) seals are members of the Canidae family - Phocidae.
• Sea lions and seals are members of the family Otariidae (Steller sea lions).
• Walruses belong to the Walrus family.

The main difference between earless and eared seals is their ears.

• Sea lions have external ear flaps. These folds of skin are designed to protect the ear from water when the seal swims or dives.
• "True" seals have no external ears at all. Need to get very close to them to see the tiny holes on the sides of the seal's smooth head.

Another difference between seal groups is their rear flippers:

In real seals, the back flippers do not bend or tuck forward, but only backward. This prevents them from "walking" on the ground. They move on land using wave-like body movements.

Steller sea lions (fur seals and sea lions) can move on land using their back legs (flippers).

Third difference:

Fourth difference:

• Sea lions are noisy animals.
• Real seals are much quieter - their vocalizations resemble soft grunts.

There are 18 species of true seals and 16 species of eared seals.

The largest representative of true seals is the southern elephant seal. A massive male, weighing up to 8,500 pounds. (3,855.5 kg). Female elephant seals are much smaller, but still weigh more than a 2,000-pound car.

Males measure about 20 feet (6 meters) in length, with females measuring about half that length.

The smallest representative of true (earless) seals is the seal. At the seal average length body 5 feet (1.5 m) and weight from 110 to 150 pounds (that's 50 - 70 kg). Unlike other seals, male and female seals are approximately the same size.

The seal is the most common seal species in the Arctic, according to study National Administration oceanic and atmospheric phenomena(NOAA).

Of the 16 species of eared seals, seven are species of sea lions.

One of the most known species, according to NOAA, is considered a California sea lion. IN wildlife these animals live along the west coast of North America. They can often be seen basking on beaches and piers.

Males average about 700 pounds (315 kg) and can reach weights of over 1,000 pounds (455 kg). Females weigh on average 240 pounds (110 kg).

Natural environment of seals (seals)

True seals usually live in the cold ocean waters of the Arctic and off the coast of Antarctica.

The harp seal, ringed seal, akiba, Icelandic hooded seal, bearded seal, spotted seal, bearded walrus and lionfish live in the Arctic.

Crab eater, Weddell, leopard seal and Ross seals - live in Antarctica.

Fur seals and sea lions live in the North Pacific Ocean between Asia and North America, and off the coast South America, Antarctica, South West Africa and southern Australia. They can spend about two years in the open ocean before returning to their breeding grounds.

Some seals make caves in the snow. Others never leave the ice and poke breathing holes in the ice.

What do seals eat?

Seals primarily hunt fish, but they also eat eel, squid, octopus and lobster.

Leopard seals are capable of eating penguins and small seals.

The gray seal is capable of eating up to 10 pounds (4.5 kg) of food per day. He sometimes skips meals for several days in a row, and lives off the energy of stored fat. And often it stops feeding completely - during the mating season it does not feed for several weeks.

All pinnipeds - from true seals (earless) to eared seals (steller sea lions) and walruses (tusked odobenids) - are carnivores. They are related to dogs, coyotes, foxes, wolves, skunks, otters and bears.

How do Squirrels appear?

When mating season arrives, male seals will make deep guttural sounds to attract the attention of females. The male seal also calls other males to a duel using sounds.

Seals are very territorial animals when it comes to mating. They will fight for the right to mate, striking and biting each other. The winner gets the opportunity to mate with 50 females in their area.

The female's pregnancy lasts about 10 months. When they feel it is time to give birth, some of them dig nests in the sand, where they give birth to their young. Other seals lay their babies directly on the iceberg, on the snow.

Squirrels are the name given to seal puppies.

Seals and sea lions only have one pup per year. Mothers will feed the squirrels on the ground until they develop waterproof fur. This may take about 1 month.

Females will mate and become pregnant again as soon as her squirrel is weaned.

Males are not able to mate until they are 8 years old because they need enough a big increase and enough strength to win a mating fight.

A few other facts about seals

All pinnipeds - seals, sea lions and walruses - are protected under the Marine Mammal Protection Act.

Most seals are not considered endangered according to the Red List International Union Nature Conservation (IUCN).

However, there are a few exceptions.

The Caribbean seal was declared extinct in 2008.

• The Galapagos seal and the monk seal are both critically endangered.
• Some local groups, such as Gray seals in the Baltic Sea, are also at risk.
• Northern fur seals and hooded seals are also vulnerable.

Northern seals, Baikal seals and Ursula seals are also vulnerable animals. They are being bred at the New England Aquarium in Boston.

The crabeater seal, among the seal species, has the largest population in the world. It is estimated that there are up to 75 million individual individuals.

The Elephant Seal has what is called "smoker's blood" - it has the same amount of carbon monoxide in its blood as a person who smokes 40 or more cigarettes a day. Scientists believe that this high level of gas in the blood protects them when they dive into the deep levels of the ocean.

Harp seals can stay underwater for up to 15 minutes.

The Weddell Seal results are even more impressive. Their record for staying underwater is 80 minutes. They only come up to grab air when they find holes in the layers of ice above the ocean.

Bay of Farallones National marine reserve California is home to one fifth of the world's seals. These marine mammals They believe they have found a safe refuge within the reserve.

Big mustachioed muzzle with expressive eyes, smooth body, strong tail and paws - who doesn’t know a seal, who hasn’t seen it at least in a picture or on TV! They are often confused with walruses, but they are completely different animals. What are their features and how many types of seals are there?

Who is a seal

Seals belong to the class of mammals that live mainly in the Arctic region. These are animals with flippers instead of limbs; it is for this reason that seals (like their relatives, walruses) were previously called pinnipeds. Now this name is not used, being considered obsolete.

Among seals, there are two families - true and eared seals.

Walrus and seal

Many people confuse walruses and seals. It is worth clarifying the difference between these animals. So, firstly, there are many types of seals, but there is only one walrus. It is larger than a seal in size and weight - at least twice as large. The walrus has large fangs - in other words, tusks, with the help of which these animals get food, fight and simply survive. The seal does not have these.

Walruses do not have ears (this is how the rhyme came about), but eared seals (you can guess this from their name) have auricles. The whiskers of walruses are thick and wide, while those of seals are thin and narrow. The first ones have almost none hairline, the second has it.

Walruses are peaceful towards each other and always stay in groups. There are skirmishes between seals (for example, over territory during the mating season); they often prefer isolation. At the same time, seals are more “talkative”; you can always hear some sounds from them. Walruses are silent people.

Earless and eared: what is the difference

As mentioned above, previously seals were called pinnipeds, but not now: according to some researchers, true and eared seals different origins. This is their main difference.

The former are the closest relatives of mustelids. That is why they have such an elongated body, like a spindle, which is comfortable to control in water, and short (in relation to the body) limbs. These seals were in the water for the first time in the North Atlantic Ocean. But their eared brothers (like walruses) originated from... bears! A small head, brownish fur color, tiny ears - all this indicates that it belongs to the bear family. They came off land in the Pacific Ocean.

Among other things, these types of seals differ in their flippers. Long-eared ones are able to step on their hind limbs and walk on the ground with them, but real ones are deprived of this ability: when they move on land, the flippers simply drag behind them. But these animals actively use their hind flippers in the water, swimming with their help. For their eared counterparts, the forelimbs are the means of swimming, and they use the hind limbs as a kind of “rudder”. Another difference between these seals and each other is that real ones do not have ears (for this feature they are sometimes called earless).

Origin of Species: A Controversial Issue

The version of the different origins of seals has its opponents. Thus, some scientists argue that pinnipeds appeared approximately fifty million years ago, when neither the mustelidae family nor the bear family existed. Such researchers tend to assume that both true and eared seals nevertheless originated from common ancestor, belong to the family of pinnipeds and are included in the suborder of canine-like arctoid predators, which, in addition to them, also includes raccoons, canids, mustelids and bears.

Real seal: features

In addition to the already mentioned characteristics of the appearance of a real seal, it must be said about the short neck and the same tail, the first being inactive. Vibrissae are usually up to ten pieces, they are quite hard. It is the whiskers that help seals navigate in the water: they do not rely on vision, but with the help of their whiskers they catch obstacles and successfully overcome them. The front flippers of these animals are even shorter than the hind ones and are located closer to the head. The size and weight of a real seal ranges from one and a half to six and a half meters and from ninety to three and a half thousand kilograms.

Some species of seals do not have hair, but it is usually rough, not fluffy, and comes in a variety of colors. Characteristic of seals seasonal molt. Babies are born with thick, often white and very soft fur, which is replaced after three weeks. Pregnancy in females lasts from two hundred seventy to three hundred and fifty days, and reproduction (as well as molting) occurs on ice. The peculiarity of real seals is that mothers stop feeding their young with milk quite early, and for several weeks the babies feed only on accumulated fat reserves (since they themselves are not yet able to provide themselves with food). In general, real seals eat fish, crustaceans, and mollusks. Some species even hunt penguins.

Representatives of the real seal

Below are the types of seals, names and photos of individual ones. There are 13 genera of earless seals:

These thirteen genera include, according to various sources, from eighteen to twenty-four various types. The most ancient is considered to be the Puyila, which lived in the Canadian Arctic.

Eared seal: features

Talking about appearance eared seals, it should be noted, first of all, that females and males are easy to distinguish by size: males grow up to three and a half meters, females - only up to one. The weight of these species, compared to real seals, is quite small - from one hundred fifty to one thousand kilograms. The color of the coat, as already mentioned, is brown, the hair itself is hard and coarse. The neck is long, the tail, on the contrary, is short. The hind limbs have claws, but the front ones do not. Moreover, they are quite large - a quarter of the entire body size of the animal.

Eared seals are quite active. They do not like ice, and prefer to molt and reproduce on the shore, but winter in the sea. Pregnancy of females is approximately the same in duration as that of real seals, but they feed their babies with milk longer - about four months. After this, the cub is able to take care of its own food. Eared seals, by the way, almost do not eat crustaceans - their diet mainly consists of fish, shellfish, and krill. Some species are capable of eating the young of other seals, penguins, and birds.

Species of eared seal

The list of species of seals of this type includes fourteen to fifteen (data vary) items, which are included in seven genera of two subfamilies. They are as follows (we will list a few):

1. Fur seals (northern, south American, subtropical, etc.).
2. Sea lions (steller sea lion, New Zealand, Galapagos and others).

Previously, there was another type of seal - the Japanese sea lion, but now it is considered extinct, since since ancient times there has been a global hunt for seals and lions.

Habitat

True seals love cold and temperate waters. They are mainly found in subpolar latitudes, but the monk seal prefers “hotter” terrain - it is found in the tropics. In addition, among the real seals of all species in the world there are freshwater ones that live in Lake Ladoga, Lake Baikal and Finland.

As for the “eared animals,” they live exclusively in the Pacific Ocean - if we talk about the Northern Hemisphere. But in the South they can be found in the south of South America, as well as near Australia - in the Indian Ocean.

Types of seals in Russia

Of the real seals, the fauna of our country can boast of nine species (this does not include the endangered monk seal: there are only ten pairs of it in the Black Sea). Eared seals in Russia are represented by only two species: the northern fur seal and the sea lion (another name is the northern sea lion).

Of all the seals living in our country, only the Baikal seal, spotted seal (spotted seal), sea ​​hare and harp seal (all of them are real).

Protected species of seals

Many seals, unfortunately, exist on the verge of extinction. Therefore, they are listed in the Red Book and are specially protected animals. Among the real seals there are two such species - monk seals and the Caspian seal. The first one is generally marked as endangered - there are no more than five hundred of them in the world today. As for their long-eared counterparts, the sea lion is rare today, the population of which is no more than seventy thousand.

Although eared and earless seals differ in many ways from each other, they also have similarities and features that are characteristic of these animals.

1. Earless seals are slow on land, but feel great in the water - they can reach speeds of up to twenty-four kilometers per hour. Eared seals are active both on land and in water; their maximum speed- twenty-seven kilometers per hour.
2. They are predators. The fish is not chewed, but swallowed whole. Maximum - can be torn apart large pieces(they have very sharp teeth).
3. They do not have lacrimal glands, but they can cry.
4. The Baikal seal is a species of seal living in fresh water.
5. To find out how old a dead seal is, count the circles at the base of the fangs.
6. With the help of fat, seals maintain good buoyancy.
7. The seal pulse in its normal state is from fifty to one hundred and twenty beats per minute, but when diving it is only four to fifteen beats.
8. They have excellent hearing and very poor eyesight.
9. Thanks to their white baby down, newborn seals are called pups. Belek is hunted by poachers due to its softness and density. Every year he dies for this reason. a large number of seal babies.
10. They detect odors at a distance of up to several hundred meters.
11. They breed once a year.
12. To get rid of fur during molting, seals help each other by scratching their backs.
13. Seals have very sensitive sleep.
14. The name of the eared seals was given at the beginning of the nineteenth century by the British zoologist John Gray.
15. The most numerous species of seal is the crabeater.
16. Eared seals waddle along the ground.
17. They can “accidentally” swallow stones along with food - up to eleven kilograms of stones were found in the stomachs of dead animals.

We are all touched when we see a seal - especially if we come to the dolphinarium. But, while rejoicing at meeting this cute animal, we must not forget that it is we, humans, who are the reason for the decrease in its population. This means that we can do everything to prevent this from happening.

Specialization went in a special direction in another group of quadrupeds - in the order of pinnipeds, the most characteristic representatives of which are the so-called true seals, among a dozen species common in the seas washing the shores of the USSR, and in some of our inland waters (Fig. 385, 386).

Seals stay in the water almost constantly - there they chase prey, rest, and sleep, and go out onto hard ground (most often on ice floes). for a long time only during the breeding and molting season. Thus, having become aquatic animals, they did not lose contact with land, which was reflected in their external and internal structure.

Their body has a characteristic streamlined shape: it is valval, with a short and thick neck (meaning?) and with hind limbs stretched back, in outline representing some similarity fish tail. The limbs of seals are short, and their shoulder and thigh sections are hidden in the body, and the paws visible from the outside have been transformed into something like fins - into flippers.

The front flippers, like the paired fins of a fish, control turns, and when moving on the ground or on ice, they allow the seal to crawl, clinging to uneven ground with its claws. The hind limbs always remain extended back and do not take part in movement on land, but in water they serve as a powerful organ of movement.

In the skeleton of the hind legs of seals there is a curious feature, due to the uniqueness of the work they perform: they face each other with their soles and are wide flippers that forcefully push out the layer of water separating them, throwing it back like a steamship propeller. And we can see (Fig. 387) that on them the outermost fingers are the most developed, longest and strongest - I (thumb) and V (little finger), that is, exactly those that have terrestrial mammals First of all, they undergo reduction (compare with the limbs of paired and odd-toed ungulates - Fig. 443 and 460).

The short tail is hardly noticeable and does not play any role in the movement of the seal.

From the smooth surface of the body of real seals natural selection He also removed the external auricles that interfered with the speed of progress, turning them into valves with which diving seals close their ear openings (special valves also close their nostrils during this time).

The fur coat, which, when the seal is constantly in aquatic environment could no longer serve as a fur coat for him, consists of short and smooth bristles, tightly fitting to the body without undercoat; Such a garment, smooth to the point of glossiness, can be compared in its meaning to the equally slippery scaly covering of fish.

On the head of a seal, in addition to the general fur, there are well-developed tactile vibrissae - whiskers.

The absence of a fur coat is compensated by the strong development of subcutaneous fat, which gives the seal’s body its roundness. In addition to preserving heat, a thick fat layer reduces the volumetric weight of the seal; This is also facilitated by the subcutaneous air sac discovered in recent years, located on the right side of the animal and having a connection with the trachea (therefore, it is possible that the air supply contained in the bag, in addition to its hydrostatic value, allows the seals to remain under water even longer).

By general character The adaptive characteristics of four-legged seals are somewhat reminiscent of penguins among birds.

Research in recent years has found that seals can dive to depths of 320–350 m and remain underwater for up to 10 minutes. So they can dive under polar ice, then floating out in the gaps formed between the ice floes. At the same time, it was noticed that seals under water make peculiar clicking sounds; It is likely that they allow seals to use echolocation to determine the location of such breeding grounds from under the ice.