Walruses are one of the most recognizable inhabitants of the north. They have flippers instead of the usual legs, behind a tail resembling a fish. And they also have very large fangs-tusks, by which they cannot be confused with other animals, and a unique resistance to the harsh cold climate, which is why the word walrus has even become a household word. These large marine mammals are the only species of their kind in Arctic waters.
Species origin and description
According to the zoological classification, walruses belong to the walrus family and to the pinnipeds order. That is, they have flippers instead of legs. Distant relatives of walruses are eared seals, to which they are very similar in appearance. For a long time, all pinnipeds were considered one order, but according to modern ideas, only eared seals are related to walruses, and real seals belong to a completely different line.
In fact, both pinnipeds come from different ancestors, and the similar shape of the body and limbs is explained by the same living conditions. The eared seal and walrus lineages diverged approximately 28 million years ago. The walruses themselves in their modern form formed about 5-8 million years ago and lived in the Pacific region. They have inhabited the Arctic waters for about 1 million years.
There are three separate walrus subspecies with non-overlapping ranges and slight differences in appearance, these are:
- Pacific walrus;
- Atlantic walrus;
- Laptev walrus
Although, based on the results of DNA studies and the study of morphometric data, scientists began to believe that it was necessary to abandon the consideration of the subspecies of the Laptev walrus as an independent one. Despite the isolation of the range, these walruses can be considered the extreme western population of the Pacific subspecies.
Appearance and features
The body of a walrus is very massive and quite large. The length of an adult individual reaches a value of 4 to 5 meters, and body weight can reach up to one and a half tons. The females are smaller. The head of a walrus is disproportionately small compared to its body, so it seems to be a small growth on its mighty neck.
The muzzle of the animal is covered with numerous thick and hard, vibrissae whiskers, the thickness of which can reach 1 or 2 mm, and the length is from 15 to 20 cm. The walrus has no external ears, the eyes are rather small and short-sighted. Vibrissae on the muzzle of the animal resemble a brush in their appearance. They are used by walruses when searching for underwater mollusks and when navigating along the bottom, since at great depths under the ice floes there is not enough light, and vision begins to play a secondary role.
Walruses have upper fangs that are extremely developed, quite elongated and directed far down beyond the jaw. They are called tusks. With them, the walrus furrows the bottom, trying to dig out mollusks and other living creatures hidden in the sand. When moving on ice floes, a walrus may use its tusks as a hooking aid. But it must be borne in mind that this is not their main purpose. Sometimes the tusks are damaged and the walrus loses them. This happens especially often in captivity, due to the hard concrete floors in the enclosures.
An interesting fact: tusks can be up to a meter long and weigh up to 5 kg. Often the tusks are used for fights, so the male with the larger tusks dominates.
The very thick skin of the animal is completely covered with short adjacent yellow-brown hair. But with age, body hair becomes less, and in fairly old walruses, the skin is almost completely bare. The skin itself has a dark brown color.
The limbs of the walrus, like those of other pinnipeds, are flippers. But they are more adapted to movement on land, unlike seals. Therefore, walruses can walk on land, and not crawl like other pinnipeds. The soles are callused. On land, walruses are quite clumsy, moving with difficulty. But they are excellent swimmers and feel very free in the water.
Where does the walrus live?
Walruses live around on the shores of the Arctic Ocean around the North Pole. Their range is circumpolar. You can meet animals on the northern coasts of Europe, Asia, as well as in the coastal waters of North America and many Arctic islands. But unlike seals, walruses avoid both open water spaces and pack ice, so they try to stay close to the coast.
In general, walruses prefer to live where the depth to the bottom is no more than a hundred meters. Since most of their diet consists of bottom living creatures, the less you have to dive and spend energy, the easier it is for animals. But at the same time, almost any walrus is able to dive to a depth of 150–200 meters.
An interesting fact: walruses can slow down their heart rate while diving. And a large layer of subcutaneous fat helps them withstand low water temperatures, which is a good heat insulator.
Animals have seasonal migrations, but they are very short. In winter, walrus populations move south, but only for 100–200 kilometers. For such large animals, this is very little.
The largest number of walruses lives on the Chukchi Peninsula, on both sides of the Bering Strait, and many colonies also live on the Labrador Peninsula. Less walruses are found in the western and central parts of the coast of Eurasia. Representatives of the Atlantic subspecies live in the vicinity of Greenland and Svalbard.
These walruses are also found in the western part of the Russian Arctic. An isolated Laptev population of walruses is localized in the central and western regions of the Laptev Sea. This subspecies is the smallest.
What does the walrus eat?
The bulk of the walrus diet consists of bivalve mollusks and other benthic invertebrates, which are harvested at depths of up to 50–80 meters.
The following can also serve as food:
- Some species of spiny lobsters;
- Polychaete worms.
Less commonly, walruses eat octopuses and holothurians. In extreme cases, some species of fish turn out to be food, although walruses usually do not pay attention to fish. Also, walruses can eat other pinnipeds, for example, baby seals or ringed seals, but this is extremely rare and in exceptional cases, when there is not enough ordinary food for everyone. Only individual individuals attack, so there is no need to talk about the massive nature of eating other animals. In very rare cases, walruses may attack landed birds.
On average, in order to get enough, an adult walrus needs to eat up to 50 kg of shellfish or other food per day. The extraction of food occurs as follows. First, the walrus, with its powerful fangs, plunges into the sandy or muddy bottom, “plows” it and uproots the shells from there. Their shell is erased by intensive movement of flippers, the surface of which is covered with multiple hard calluses, and the meat is eaten. Similarly, worms and crustaceans are harvested. Their walruses are actually swept from the bottom to eat. The search for food occurs with the help of vibrissae located on the muzzle of the animal.
Peculiarities of character and lifestyle
Walruses are herd animals. Usually the size of each herd is from 20 to 30 walruses, but on some rookeries hundreds and even thousands of animals come together. Each pack is dominated by the strongest and largest male. The rest periodically sort things out with him and try to take away the title. The subject of the dispute is almost always females.
In a herd, animals often lie very close to each other, due to the limited land area or ice floe. Often you have to lie on your side, sometimes putting your head on a neighboring walrus. And if there is very little space, then they can lie in two layers. The whole rookery is constantly «moving»: some animals go into the water to eat or cool down, and other walruses immediately return to their place to sleep.
Interesting fact: according to At the edges of the walrus rookeries, there are almost always sentinels who, having noticed the danger, immediately notify everyone else with a loud roar. After such a signal, the whole herd rushes into the water as one.
In relation to other animals and to each other, walruses are for the most part peaceful and friendly. In addition, female walruses have a very developed maternal instinct, so they selflessly protect their cubs in case of danger, and take care not only of their offspring, but also of other people's cubs. They are also very sociable. Any adult walrus in the herd allows any walrus to climb on its back and lie there to rest.
Social Structure and Reproduction
Walruses are quite peaceful and calm animals, but during the mating season, which occurs at the end of April or early May between males very often there are battles for females. In a fight, they use their powerful fangs-tusks, but do not leave strong defeats on the opponent's body. Walruses have very thick skin and a powerful layer of fat, which prevent serious injury to internal organs.
At the end of April, male walruses accumulate the largest amount of mature sperm, and they are ready to fertilize the female. Females, in turn, are also ready for fertilization during this period, and already in mid-May they begin to develop corpora lutea of pregnancy.
After mating, all walruses continue their quiet life in their herd. Pregnant females will bring their offspring in a year. The only baby is always born. Its weight reaches 60-70 kg, length is about a meter. A small walrus is able to swim in water from birth, this helps him survive in case of danger, and he dives after his mother.
The lactation period for walruses is very long – as much as two years. Therefore, walruses breed only once every 4–5 years. The female can become pregnant more often only if the previous cub has died. When walrus cubs grow rather large tusks, lactation stops and the animal switches to independent nutrition. Males become sexually mature by six to seven years of age, females a little earlier.
The cubs continue to live within the same herd with their parents, but as independent individuals.
Natural enemies of walruses
Walruses are large and very strong, so very few people could harm them. Of the land animals, only the polar bear risks attacking walruses, and he does this in a certain way. A bear guards a walrus on the edge of an ice floe or near an ice hole from which a walrus will emerge.
It is at the moment of emerging that the bear must strike him, so that he can then cope with the carcass. That is, if he does not kill or knock out the walrus with one blow, then the walrus will resist him. In a battle between a walrus and a bear, the second one can be seriously injured by the tusks of a sea giant.
Bears are also very dangerous for newborns and even small walruses. Bears can attack them directly on land, on ice. Babies are not able to show strong resistance and most often die in the clutches of predators.
There are cases of killer whale attacks on walruses. They are almost 3 times larger than walruses, and 4 times heavier than them, so the walrus cannot protect itself from killer whales. He manages to escape only if he gets out on land. Killer whale hunting tactics are always the same. They wedge into a flock of walruses, separate it, then surround a separate individual and attack it.
The main enemy of walruses is a man. For the sake of meat, fat, skin and tusks, people often hunted walruses. Killing one walrus can feed a family for several months, so many walruses died at the hands of man. But not only hunger makes people kill these peaceful animals, they are also driven by hunting passion.
Unfortunately, therefore, a lot of walruses died for nothing. They breed rather slowly, and the number of walruses has greatly decreased. It will take a lot of time to increase it, and, whatever one may say, this process cannot be accelerated.
Population and species status
There is no exact information about the number of walruses today. According to rough estimates, the number of representatives of the Pacific subspecies is at least 200 thousand individuals. The number of the Atlantic walrus is an order of magnitude lower – from 20 to 25 thousand animals, so this subspecies is considered threatened. The smallest population is the Laptev population. There are only 5 to 10 thousand such walruses left today.
Not only human activity, but also global climate change has a significant impact on the population of these animals. In particular, there is a reduction in the extent of pack ice and its thickness. Namely, on this ice, walruses form their rookeries for mating and childbirth during the reproductive period.
It is believed that due to climate change, there has been a decrease in suitable resting places for walruses near the optimal areas for their feeding. Because of this, females are forced to be away longer in search of food, and this also affects the feeding of the cubs.
Due to the decline in the number of walruses, their commercial production is now prohibited by law in all countries. To a limited extent, fishing is allowed only to indigenous and indigenous peoples, whose existence is historically closely connected with the extraction of walruses.
The Atlantic subspecies of the walrus and the Laptev walrus living in Russian waters are included in the Red Book of Russia. Their coastal haulouts are protected, and fishing has been prohibited since the fifties of the XX century. Rookery sites have been declared nature reserves, and industrial activity in their vicinity has been reduced to a minimum. But besides this, no special and additional measures for the protection of walruses have been worked out in detail so far.
Joint international efforts have managed to increase the natural growth of walruses. On average, now it is about 14%, which is 1% higher than the mortality of these animals. Along with the actions already taken, it is also advisable to organize research on habitats and carefully monitor the abundance on a regular basis.
There is an assumption that, in order to maintain the population, it makes sense to protect not so much the walruses themselves, but the animals they feed on. But this is just one of the potential measures. There is also an opinion that the decline in numbers is associated with climate change. This greatly complicates the artificial restoration of populations.
An effective measure is only the limitation of chemical pollution of the seabed and water, as well as the limitation of disturbance factors such as engine noise from helicopters and passing ships. Then the walrus will be able to restore its population and possibly begin to restore its position in the global ecosystem.