Most river mammals spend only part of their lives in water. Animals such as the river otter and the swimming rat live on land and venture into the water in search of food.

1. Hippopotamus.
A hippopotamus peers out of an algae-covered lake in Kenya's Masai Mara Game Reserve. These massive mammals cool their huge bodies in African lakes, ponds and rivers for up to 16 hours a day every day. And although these animals can hold their breath for about half an hour, they usually do not submerge completely under water, leaving the top of their heads on the surface. At night, hippos leave the water and come to land in search of food. If they stay on land too long during a hot day, the animals quickly become dehydrated.

2. Hippopotamus.
The Zambian hippopotamus sends an aggressive message by displaying its sharp teeth, which can reach lengths of 20 inches (51 centimeters). Males use a wide open mouth when fighting to determine which animal is dominant. Sometimes a simple show of force is not enough, and such behavior leads to potentially deadly battles. Hippos are also dangerous to humans.

3. Manatee.
Manatees swim slowly through shallow, warm coastal waters and rivers. For example, such as this crystal clear river in Florida - Crystal River, which is shown in this photo. The large mammals (up to 1,300 pounds or 600 kg) are born underwater and remain there throughout their lives, although they must come up for air every few minutes. Known as sea cows, they are voracious herbivores, feeding on a variety of sea grasses, weeds and algae.
Several different species of manatees live along the Atlantic coast of North and South America, the west coast of Africa, and in the Amazon River.

4. Muskrat.
Muskrats are frequent inhabitants of wetlands, swamps and ponds, where they make their burrows by digging tunnels in marshy banks. This large rodent has a foot-long body and a flat tail almost as long as its body. Muskrats are well adapted to water and begin to swim 10 days after birth. Perhaps best known for their highly developed communication skills, muskrats exchange information with each other and ward off predators with their distinct scent.

5. Baikal seals.
There are a large number of seals living in the world, but only one species is truly freshwater - the Baikal seal. These seals live in the lake of the same name on the territory of the Russian Federation, which is the deepest in the world. Although new generations of Baikal seals are born every year in such colonies, this species is not in serious danger. The main threats are poaching, as well as pollution from paper and pulp production, which are located near the lake.

6. Amazonian dolphin.
To track food (small fish and crustaceans) in murky river waters, the charismatic Amazon dolphin uses echolocation. During their annual leashes, these dolphins actually swim through the flooded forests and hunt among the trees. The bright hue (often pink or very pale) and natural curiosity of this dolphin species make them easy targets for fishermen poachers who illegally catch them to use as catfish bait. The population of these individuals has decreased significantly in recent years. Among the locals inhabiting the shores of the Amazon, these dolphins have long been considered supernatural creatures that could take on human form.

7. Capybara.
The world's largest rodent, the capybara grows to 4 feet in length (130 cm) and weighs about 145 pounds (66 kg). These moisture-loving mammals reach this size by eating grasses and aquatic plants.
In most cases, these mammals live in watery areas, to which they are physically well adapted. They have webbed feet, thanks to which they swim well and can dive under water for five minutes or more. Capybaras live in Central and South America, inhabiting the lakes, rivers and wetlands of Panama from southern Brazil to northern Argentina.
The Nature Conservancy is working with partners to protect capybara habitat, including the watery grasslands of Llanos. The group is working with local landowners to create private reserves in critical habitat areas and helping to secure more resources for a 63,000-acre (25,500-hectare) conservation area in Casanare province in northeastern Colombia.

8. Capybaras.
The eyes, ears and nostrils of capybaras are located high on the head, so they remain on the surface when the animal is in the water. These social mammals move and live in alpha male-dominated groups and work together to defend their home and feeding territory. People hunt (and also farm) capybaras for their skin and meat, which is especially popular during Lent - Catholics in South America consider the animal an acceptable alternative to beef or pork.

9. Beaver.
Beavers are ecological engineers, second only to humans in their ability to significantly alter the landscape to their liking. Using their powerful jaws and teeth, they cut down trees by the dozens and build dams of wood and mud 2 to 10 feet (1-3 meters) high and over 100 feet (30 meters) long. And they do this so that the filling waters flood the nearby fields and forests. In the resulting lakes, which are sometimes enormous in size, beavers build their homes from branches and mud.

10. Beaver.
Although they are quite clumsy on land, beavers swim easily in the water thanks to their webbed feet and paddle-shaped tail, which help them reach speeds of up to 5 miles (8 km) per hour. These mammals also boast a sort of natural diving suit in the form of their oily, water-resistant fur.
Beavers eat aquatic plants, roots, leaves, bark, and branches. Their teeth grow throughout their lives, so they simply need to chew on trees to prevent them from growing too long and crooked. A single beaver chews down hundreds of trees each year, typically gnawing down a tree 6 inches (15 cm) in diameter in just 15 minutes.

11. River otter.
This sleepy river otter is actually very playful. The water-loving mammal is always willing to dive under water and can move gracefully thanks to its webbed feet and paddle-shaped tail. Otters have specially designed ears and nostrils that close underwater, as well as water-repellent fur. Young otters begin to swim at the age of 2 months. River otters live in burrows along the edges of a river or lake in close proximity to the fish on which they feed.

12. Platypus.
The platypus is an incredible mixture of different animals: its furry body resembles that of an otter, its beak like that of a duck, and its webbed feet and paddle-shaped tail like a beaver. Like all these animals, the platypus is a strong swimmer and spends most of its life underwater. Unlike otters and beavers, they lay eggs. Male platypuses have poisonous stings on their hind legs. These animals build their burrows at the very edge of the water and feed on underwater worms, mollusks and insects.

Having gone through a long path of evolutionary development, they turned into those whom we know and can observe with you at the present time. Although, in the scientific world there is another version of the origin of certain speciesmarine mammals. A number of scientists put forward the version that some species originated from land animals, and then returned to the sea elements for the second time. And today we will talk about this.

Bottlenose dolphins (or bottlenose dolphins)

Marine mammals and their diversity

Today there are quite a few typesmarine mammals, despite the fact that their ancestors had to undergo significant changes. After all, over thousands of years, conditions for development and reproduction have not always been favorable. Some animal species became extinct, while others, on the contrary, found the opportunity to develop, reproduce and adapt to their environment. This is how modern marine mammals, many of which are familiar to you.

Eared seals

Marine mammals are a large group of mammals whose life is fully or half connected with the aquatic marine environment, i.e. These are animals that spend their entire lives, or half their lives, in sea water. I must say that everything marine mammalsare divided into systematic groups, which we will discuss later.

Currently there are about 128 species marine mammals, which is approximately 2.7% of the total number of all existing mammals on Earth. These animals are very diverse, among them you can find very small in size and weight - from just a few kilograms, to giant ones, whose weight can reach tens of tons!

Great killer whale

Taxonomy of marine mammal species

All existing types marine mammalsare divided into orders, suborders, groups and families.

• First squad - . It includes two families. The first family is manatees (Trichechidae). There are three known species of manatees (American manatee, African manatee and Amazonian manatee). The second family is dugongs (Dugongidae). Currently, there is only one representative of this family - the dugong.

Dugong

• Second squad - . This order includes two suborders. The first is baleen whales (Mysticeti), which includes about fifteen species of whales, the second is toothed whales (Odontoceti). The suborder of toothed whales includes about 73 species of these large marine mammals.

Sperm whale

• The third, most numerous order is the carnivores (Carnivora). It is divided as follows: it includes a large group, which, in turn, is divided into three families:

- 1) true seals (Phocidae) - approximately 20 species;

– 2) eared seals (Otariidae) – approximately 16 species;

- 3) walruses (Odobenidae) - only one species.

Walrus

It is worth noting that quite recently pinnipeds were considered an independent order. The order in question is further divided into the mustelidae family (Mustelidae), which includes the sea otter (Lontra felina) and sea otter (Enhydra lutris), and another family, the bears (Ursidae). The only representative of this order belongs to the bear family - the polar bear (Ursus maritimus).

Sea otters

In this section we talked in general terms about the typesmarine mammals, in the following articles, we will definitely dwell on each of them in detail. And now, we bring to your attention the incredible documentary film “The Great Blue Whale”, we are sure that you will like it:

The streamlined, often torpedo-shaped body gives them an external resemblance to fish. However, cetaceans are warm-blooded, breathe atmospheric air, bear a fetus in the uterus, give birth to a fully developed calf capable of independent existence, which the mother feeds with milk, and the remains of hair are visible on their body. By these and some other characteristics they are similar to other mammals, and the general plan of their structure also indicates that they belong to this class animals .

The body of cetaceans, round in cross-section, tapers towards the end and ends with a pair of wide caudal fins, flattened in the horizontal plane. These fins, although devoid of a bony skeleton (there is cartilaginous supporting tissue inside them), serve as the main organ that ensures the animal’s forward movement. The pectoral fins, or flippers, correspond to the forelimbs of land mammals; their carpal parts are not dissected externally, and sometimes are fused internally, forming spade-shaped structures. They serve as stabilizers, “depth rudders”, and also provide turning and braking. There are no hind limbs, although rudiments of pelvic bones have been found in some species. The neck is very short, since the seven cervical vertebrae common to mammals are greatly shortened and fused into one or more plates, the total length of which does not exceed 15 cm.

The body of cetaceans is covered with smooth, shiny skin that facilitates gliding in the water. Under the skin there is a layer of adipose tissue (blubum) ranging from 2.5 to 30 cm thick. Fat protects the body from hypothermia and helps retain water in the body that would otherwise diffuse into the environment; body temperature is maintained at approximately 35? C. Animals do not need fur, since the fat provides sufficient thermal insulation, however, in the embryonic stages and in adults, sparse hair can be found on the snout.

The head is very large and wide. The neck is so shortened that outwardly the boundary between the head and the body is not noticeable. There are no external ears, but there is an auditory canal, which opens through a small hole in the skin and leads to the eardrum. The eyes are very small, adapted to life in the sea. They are able to withstand high pressure when the animal is immersed to great depths; large, fatty tears are released from the tear ducts, which help to see more clearly in the water and protect the eyes from the effects of salt. Nostrils - one (in toothed whales) or two (in baleen whales) - are located in the upper part of the head and form the so-called. blowhole. In cetaceans, unlike other mammals, the lungs are not connected to the oral cavity.

The animal inhales air, rising to the surface of the water. Its blood is capable of absorbing more oxygen than that of land mammals. Before diving into the water, the lungs are filled with air, which, while the whale remains under water, is heated and saturated with moisture. When the animal floats to the surface, the air it exhales forcefully, in contact with the cold outside, forms a column of condensed steam - the so-called. fountain. Thus, whale fountains are not columns of water at all. In different species they are not the same in shape and height; for example, the fountain at the top of the southern right whale bifurcates. The exhaled air is forced through the blowhole under such strong pressure that it produces a loud trumpeting sound, which in calm weather can be heard from a great distance. The blowhole is equipped with valves that close tightly when the animal is immersed in water and open when it ascends to the surface.

The cetacean order is divided into two suborders: toothed whales (Odontoceti) and baleen whales (Mysticeti). The former are considered less specialized; These include, in particular, beaked whales, sperm whales, killer whales, as well as smaller forms - dolphins and porpoises. Sperm whales reach a length of 18 m and weigh 60 tons; the length of their lower jaw reaches 5-6 m.

The teeth of baleen whales are replaced by long, fringed horny plates (baleen) that hang from the upper jaw and form a filter for straining small crustaceans and fish from the water. This suborder includes minke whales, as well as blue, humpback, dwarf, smooth, bowhead and other whales. Some blue whales reach a length of 30 m. This animal is larger than even giant dinosaurs. It can weigh as much as 150 bulls or 25 elephants.

Fossils of primitive whales, zeuglodonts ("jugular-toothed"), have been found in marine sediments of Africa, Europe, New Zealand, Antarctica and North America. Some of them were giants more than 20 m long.

A whale can reach enormous sizes, since its limbs do not have to support its body weight: in the water it is as if weightless. A large whale swimming at a speed of 20 knots (37 km/h) “generates” 520 hp of energy. With.

Whales swallow food whole and consume up to a ton of food per day. The sperm whale's pharynx is very wide, so that it can easily swallow a person, but in baleen whales it is much narrower and only allows small fish to pass through. The sperm whale feeds mainly on squid and often feeds at depths of more than 1.5 km, where pressure exceeds 100 kg/cm2. The killer whale is the only representative of the order that regularly eats not only fish and invertebrates, but also warm-blooded animals - birds, seals and whales. Cetaceans have a very long intestine and a complex multi-chamber stomach, consisting, for example, of 14 sections in beaked whales, and 4 in right whales.

The female gives birth to one baby underwater. It comes out of her body tail first. The cub is fully developed and is almost immediately able to follow the herd. It suckles for approximately 6 months and grows rapidly, reaching sexual maturity by age three, although increasing in size continues until age 12. Most large whales breed once every two years. Despite their enormous size, these animals are not very durable. Science knows very few specimens of right whales older than 20 years.

Herds of whales can commit something akin to mass suicide. Sometimes a hundred or more of their individuals wash ashore at the same time. Even if the suffocating animals are towed back to sea, they return to land. The reasons for this behavior have not yet been determined.

Whales provide humans with many useful products. People have been hunting them since ancient times, and whaling existed before the 10th century. In addition to meat, whale oil (blub), which is used to make soap and cosmetic creams, is of great value.

Ambergris is extracted from the intestines of sperm whales; this grayish substance is secreted there as a result of irritation of the mucous membrane caused by the horny jaws of swallowed squids. Pieces of ambergris weigh up to 13 kg, and the mass of its largest “nugget” is 122 kg. It contains sodium chloride, calcium phosphate, alkaloids, acids and the so-called ambrine; this substance is lighter than fresh and salt water, softens in the hands, melts at a temperature below 100? , and with stronger heating it evaporates. Ambergris was once highly valued as a perfume fixative. Currently, whaling is almost universally prohibited, since as a result of irrational mining, the whale population has greatly decreased and some of their species have found themselves on the brink of extinction. extinction. International agreements allow the capture and slaughter of individual specimens for scientific research. In addition, some peoples, such as the Eskimos, for whom whale hunting is one of the most important traditional activities, are allowed to continue it on a limited scale.

The largest group is forest animals. It includes animals that inhabit forests and bushes. Among them there are species, most of them life conducting on trees.

For example, squirrel, marten, dormouse They have sharp claws and a bushy tail, which helps them make gliding jumps. U flying squirrel And bats For this purpose, leathery folds on the sides of the body are used.

Some types of forest animals, for example chipmunks, sobo-li, lead a terrestrial-arboreal lifestyle. Live in tropical forests lemurs, sloths, gorillas, chimpanzees, having grasping paws with highly developed fingers and a tenacious tail.

Among animals leading a terrestrial lifestyle (on the ground they obtain food and breed offspring), there are omnivores ( brown bears And badgers ), predatory (foxes, wolverines, ferrets) and herbivorous species ( moose, deer, roe deer, hares). For them, trees serve as shelter and food.

Open spaces - steppes, prairies, savannas - exist on all continents. The main vegetation of such ecosystems- herbs, therefore among animals herbivores predominate. Ungulates are very diverse and numerous: antelopes, zebras, saigas, wild horses , wandering across endless expanses in search of food. They are all good runners, as they must escape from strong and fleet-footed predators - cheetahs, lions, steppe wolves.

Typical rodents for such ecosystems are: marmots, gophers, jerboas, gerbils, hamsters. Colonies of these animals may have a negative impact on the landscape and growing conditions plants.

Mammals evolved from land animals. However, some species have secondarily mastered the aquatic environment. This was reflected in the features of their external and internal structure. For example, whales, dolphins, sirens They spend their entire lives in water, so their body has a streamlined shape and is devoid of hair. They have devices for swimming - a caudal fin and flippers (modified forelimbs). Other animals, for example tulle-ni, walruses , seals , also live in water, but during reproduction come out onto land, forming huge rookeries. Material from the site

Lead a semi-aquatic lifestyle beaver, muskrat , nutria , sea ​​otter .

Their limbs are equipped with swimming membranes, so they swim well, getting food and escaping from enemies.

The structural features and lifestyle of underground mammals are associated with living in a dense environment devoid of light. The body of shrews is short, covered with thick, dense fur. The cervical region is invisible, the tail is reduced. The limbs are usually spade-shaped and have developed muscles, equipped with large claws.

Underground mammals have poor vision and have no ears. However, the organs of smell and touch are well developed. They spend almost all their time underground.

Pictures (photos, drawings)

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