Like a river dolphin. Freshwater or river dolphins (Platanistidae). Lifestyle and habitat of the river dolphin

Amazonian inia, or bouto (Inia geoffrensis). Young animals are light gray, but gradually acquire a pinkish tint with age. Their very long snout is covered with stiff hairs or bristles, apparently performing a sensory function. Amazonian inias have an average of 25–27 teeth on each side of each jaw. The front teeth are pointed, conical, and the back teeth are somewhat similar to the molars. Two types of teeth and unfused cervical vertebrae- primitive signs for cetaceans. Inya feeds on fish, including those covered with bony plates, and her teeth are often heavily worn, apparently due to chewing solid food.

According to some reports, inia may have several subspecies. These freshwater cetaceans are common in the Amazon and Orinoco basins, and during floods even penetrate into flooded forests, where they swim between trees. Looking out for food at the bottom, the ini often turn upside down, perhaps because otherwise their thick cheeks interfere with the view. Studies of the sounds they make have shown the presence of a rich repertoire of impulse signals, including echolocation signals used for searching for food and research. environment; however, no monotonous whistles were found.

The Gangetic dolphin, or susuk (Platanista gangetica), lives in the Indian rivers Indus, Ganges and Brahmaputra. Obviously, he is blind, since his eyes are devoid of a lens. However, animals compensate for this shortcoming by developing an unusual cup-shaped depression in the skull, which resembles an enlarged flashlight reflector and undoubtedly directs and concentrates echolocation signals. Studies of several living specimens of this species have demonstrated their apparently exceptional echolocation abilities. It is believed that the Gangetic dolphin eats freshwater shrimp and fish burrowing into the silt, which he catches by probing the bottom with his very long jaws. Surprisingly, this animal usually swims on its side.

The Laplata dolphin (Pontoporia blainvillei) is unique among the species of the Platanistidae family for several reasons. He lives not only in major river La Plata in South America, but also leaves it in purely marine coastal waters. Some features of his skeleton are also unusual and good development dorsal fin. Some taxonomists have proposed placing it in the Delphinidae family. This small dolphin feeds on fish, shrimps and cephalopods.

Freshwater dolphins are distinguished by the fact that their neck vertebrae are divided, as in land mammals rather than being fused into a single bone. In some species of this family, in addition to conical teeth, there are molar teeth, i.e. close in structure to the indigenous. The dorsal fin is usually very low, in the form of a crest; only in the Laplatian dolphin it is the same as in the dolphins.

In the suborder of toothed whales, the family of river dolphins is the most ancient. Initially, its representatives lived in the ocean, but due to stronger competitors and numerous enemies, they moved to freshwater reservoirs. The river variety, both in its way of life and outwardly, differs from the well-known sea dolphins.

Characteristics of the animal

If we compare river dolphin with a marine counterpart, it will become clear that freshwater is more primitive.

Family freshwater dolphins represent two monotypic genera living in tropical South American rivers, and two genera inhabiting Indian and Chinese rivers.

Now let's talk about the species of river dolphins known today.

Bowto or Amazonian inia

The first Amazonian inia described in detail French scientist D "Orbigny. Traveling around Peru, he caught this freshwater dolphin and studied his appearance well.

The natives don't hunt frost. Why?

The natives ignore ini due to the fact that the meat of these river dwellers is not solid, and there is almost no fat. Also the reason a lot mysterious stories associated with animals. According to one of them, Amazonian inia this is an evil sorceress, able to transform into a young beautiful woman with curly locks. In this guise, she lures gullible youths and destroys them.

Locals say that the sorceress appears in the city of Aigues, where she is looking for another victim. When she captivates the beauty of a man, leads him to the river bank, where he hugs the victim, screams loudly and disappears into the water depths with his admirer.

Fat can fill lamps, but no one does. Belief says that a person who does this will go blind or misfortune will befall him.

Pliny on the freshwater dolphin

The ancient naturalist Pliny was the first to describe another river dolphin, the susuku. Although the descriptions contained many inaccuracies, because he could observe the animal only in the water. The main misconception was in the information about the length of the body. According to the philosopher, it reached 7m. In fact, freshwater was no longer than 2 m.

Susuk lifestyle and structure

• The body of this river dolphin is slender.
• The dorsal fin is lunate and divided into two lobes, essentially a fold of skin.
• Slightly raised, long, thin, beak-shaped muzzle, the same width along the entire length.
• The upper jaw has a ridge surrounding the long and narrow nostrils.

Susuk lives in the basins of the rivers of Southeast Asia and the Indus. An experiment conducted by the biologist Anderson, who kept the susuk in captivity for 10 days, showed that these animals rise to the surface of the water for a moment every half a minute to take a breath.

They feed on crabs and fish. Pregnancy is expected to last 8-9 months; into the world one baby appears, for a long time remaining under maternal care, he clings to her dorsal fin with his muzzle.

Susuk are rarely hunted, mainly for meat. Especially willingly this meat is eaten. indian women who have difficulty in childbearing. According to legend, meat helps to get pregnant and bear the child safely. Monks and pilgrims, considering the animal sacred, feed it from their hands.

Chinese dolphin

The Chinese river dolphin became known less than a hundred years ago, in 1918. The animal was discovered in a freshwater lake, and it differed from the already studied marine species.

Laplata river dolphin

• It can also live in rivers and seas.
• The body length of males reaches 1.55 m. In females, the body length can reach up to 1.7 m.
• Weight - 28-35 kg.
• The hatchlings are about 45 cm long.
• The snout is long.
• Skin color is pale brown.
• The number of teeth is 210–240.
• It eats fish, crayfish and cephalopods.

The Laplata dolphin is sociable, willingly swims up to fishing boats, makes contact with a person. live those miniature dolphins at the mouth of the La Plata River and the coastal waters of Brazil, Argentina and Uruguay (between 30 and 45° S).

reproduction

The river dolphin reaches sexual maturity at the age of about 5 years. Pregnancy lasts 11 months. After the birth of the cub, the female pushes him out of the water so that he takes his first breath.

The length of the cub is 75–85 cm, and it weighs about 7 kg, the body is light gray in color. After the birth of the young, the male return to the river, and the female remains with the offspring in place (in valleys, channels). Females protect cubs from predators, lack of food, aggression of foreign males. Cubs stay with their mother until about three years of age.

Often the female becomes pregnant again without completing the lactation process. There are 5–25 months between matings.

Life expectancy is 16–24 years.

Inhabitants Barents Sea are white-faced and white-sided dolphins.

white-faced dolphin- This is a rather rare and little-studied species. It is listed in the Red Book because long time hunted for meat and fat. Today, their population is slowly recovering. White-faced dolphins live in coastal areas in schools of 20-30 individuals. Growth adult can reach three meters. And you can recognize it by its black color, white beak, wide white stripes along the body and crescent-shaped dorsal fin.

Atlantic white-sided dolphin also listed in the Red Book. It is considered a heat-loving species, so meet it in northern seas this is a rarity and a blessing. This type of dolphin is slightly smaller than the white-faced, growing up to 2.5 meters. The distinguishing feature is the long white stripe along the black body on both sides, as well as a large white or yellow spot on both sides of the dorsal fin. Unfortunately, hunting for white-sided dolphins continues to this day.

See dolphins in the Barents Sea it is possible in the region of the Rybachy Peninsula, along the Teriberskaya Bay and near the Teribersky Cape, and also extremely rarely in the Kola Bay.

Dolphins in the Baltic Sea

Inhabitants Baltic Sea are the Atlantic bottlenose dolphin and the harbor porpoise.

Atlantic bottlenose dolphin- The bottlenose dolphin family is considered medium-sized dolphins, among which the Atlantic species is considered the largest and reaches three meters in length. They are gray in color with a white belly. Bottlenose dolphins live off the coast in temperate warm waters small groups. Meet among them and couples. Bottlenose dolphins are considered the most intelligent and friendly of the cetacean family. They are very smart and often save people and animals in trouble.

Harbour porpoise. It is found in the Baltic Sea and is a very rare endangered species, which is sometimes attributed to dolphins, somewhere to whales, but in general, it is a mammal of the cetacean family. Representatives of this species are usually small in size, up to two meters maximum. The body has a dark gray color, and the belly is almost white with gray stripes along the entire body. Most often, porpoises swim alone or in small groups of up to 5 individuals.

See dolphins in the Baltic Sea you can in the Gdansk Bay, near the village of Povarovka, where they are often seen by fishermen, as well as along the Curonian Spit.

Dolphins in the Sea of ​​Okhotsk

The inhabitants of the Sea of ​​Okhotsk are the Pacific dolphin and the white whale.

pacific dolphina direct relative of the Atlantic white-sided dolphin, only slightly smaller. The largest male reaches 2.3 meters in length. Besides hallmark Pacific dolphin is black line, which runs along the lower part of the body, from the mouth to the fins and between the fins. In addition, their front fins are shorter and wider than those of other species. These dolphins live in the northern part Pacific Ocean and rush across the expanses of water in large schools of up to a thousand individuals.

Beluga whale called differently polar dolphin. This is a mammal of the dolphin family of the whale suborder, so someone considers the beluga whale a whale, and someone a dolphin. Beluga whales are born almost black, but adults are completely white. Also, this dolphin giant size up to six meters in length. Beluga whales live in flocks, and inside the flocks are divided into groups: male and female with cubs. Despite their huge size and toothy mouth, beluga whales are surprisingly kind and affectionate creatures.

See dolphins in the Sea of ​​Okhotsk possible in the Sakhalin Bay, the Amur Estuary, near the Shantar Archipelago, near west coast Kamchatka. Beluga can also be seen in the White Sea.

Dolphins in the Black Sea

Black Sea common flank somewhat smaller than the Atlantic, but the fastest. They say that in terms of speed, these dolphins do not step on some ships, breaking up to 60 kilometers per hour. White-sided dolphins live much further from the coast than bottlenose dolphins. They prefer the open sea, and in captivity they die rather quickly.

See dolphins in the Black Sea can be along the entire Crimean coast, as well as in the Anapa region.

The family of river dolphins is the oldest in the suborder Toothed whales. Initially, its representatives lived in the ocean, but later stronger competitors and numerous enemies forced them into freshwater rivers.

general characteristics

The river dolphin, when compared with its marine relative, is more primitive. The brain has fewer convolutions. Short and wide pectoral fins, the absence of a dorsal fin (instead of it there is an elongated crest), a very narrow snout, a long symphysis of the lower jaw - all these are features of its ancient ancestors, squalodonts.

The free arrangement of the cervical vertebrae allows river dolphins to turn their heads 90° in relation to their bodies. They feed on fish, mollusks and worms, which are mined not only in the water. With the help of a snout covered with a layer of hard tactile hairs, they are able to feel prey in the depths of the muddy bottom and dig it out. Unlike touch, their eyesight, on the contrary, is quite weak. But the hearing and echolocation apparatus are very developed. It is with their help that river dolphins receive information about the world around them.

If we talk about the range, then it can be called relic and broken. The family is represented by two monotypic genera inhabiting the tropical rivers of South America and two genera inhabiting the rivers of India and China. Next, consider the species of river dolphins discovered to date by zoologists.

Amazonian inia, or bowto

First detailed description The Amazonian inia was given by the French scientist D "Orbigny, who, traveling around Peru, was able to catch this animal and study its appearance.

The body length of the inia can reach 3 meters, and weight - 70 kg. It lives in the Amazon, Rio Negro, Orinoco basins. This dolphin can be called a real freshwater whale. It is slow (speed does not exceed 10 km / h), in muddy water an echolocation apparatus and a sensitive snout help him navigate. The main type of food small fish. This river dolphin very often comes up to the surface to inhale oxygen. Inii live only in small communities, no more than 5-6 individuals.

The muzzle is very elongated, blunt at the end and covered with bristles, looks very much like a beak. The upper and lower jaws contain 66-68 teeth each. They are very sharp, and the crowns are large and curved back. The semilunar shape of the flippers, the division of the caudal fin into blades, the low location of the adipose fin are typical features of the Amazonian inia. Top part her body is pale blue, while the underside is reddish pink. Elderly dolphins can be almost white. Therefore, the inia is often called the "white river dolphin".

Why the natives don't hunt the Amazonian ini

The natives never chase the frosts. The reason for this is the fragile meat and the almost complete absence of fat. Another thing is that many mysterious stories are associated with them. According to one of them, the Amazonian inia is actually an evil sorceress who can take the form of a young beautiful woman with long curly curls. In this form, she lures inexperienced gullible youngsters in order to then destroy them. According to local residents, she takes to the streets of Aigues to find another victim. And when she captivates a man with her beauty, she takes him to the river bank. There she takes the victim into her arms, publishes shout and disappears with the admirer in the watery depths.

The fat of these river dolphins can be used in lamps for burning, but no one does. There is a belief that a person who decides to take such a step will go blind or some kind of misfortune will happen to him.

Discovery of Pliny

The ancient naturalist Pliny first gave a description of another species of river dolphins - the Gangetic dolphin (susuku). And although there was a lot of inaccurate information in his descriptions, since he saw susuk only in water, it was this scientist who first drew attention to characteristics animal. The main delusion of Pliny was the information about the length of the body of the Gangetic dolphin. According to him, it reached 7 meters. In fact, it is no more than 2 meters.

The external structure and lifestyle of the susuk

This animal of the River dolphin family has a very slender body, a semi-lunar dorsal fin divided into two lobes, a long, thin, beak-shaped muzzle slightly raised upwards, which has the same width along the entire length. typical feature is the presence on the upper jaw of a ridge surrounding long, narrow, adjacent nostrils. Instead of a dorsal fin, there is only a small fold of skin. In the upper part of the body, the skin is colored grayish-black, and in the lower part it is grayish-white.

Susuk lives in river basins South-East Asia, in particular in the Ganges, Brahmaputra and Indus. In an experiment conducted by a biologist named Anderson, who kept the Gangetic dolphin in captivity for 10 days, it turned out that representatives of this species rise to the surface of the water very often (every 30 seconds), but only for a moment, because in order to take a breath, they only need a fraction of a second.

They feed mainly on fish and crabs. Presumably, the pregnancy lasts 8-9 months, one cub is born, which for a long time remains under the care of the mother, clinging to her dorsal fin with its muzzle.

The dolphin is caught extremely rarely, mainly for the sake of meat. Indian women who have difficulty in childbearing eat it especially willingly. According to legend, it helps to get pregnant and carry the child safely. Pilgrims and monks, on the contrary, consider this animal sacred and feed it from their hands.

Chinese lake dolphin

This species of animal became known in 1918, when a dolphin was first discovered in the waters of the freshwater lake Dongtinghu in China, which differs from previously discovered and already studied species. The body length was about 2 meters, weight - more than 120 kg. The dorsal part is gray, towards the belly the color brightens and turns into white. Pectoral fins wide enough, and their free end seems to be chopped off. Vision is very poor. These dolphins usually swim in flocks of 3-4 individuals, and in rare cases - of 10-12. The dorsal fin has characteristic shape, resembling a flag sticking out of the water. The dolphin feeds on eels, catfish, molluscs, catching prey from the silt.

Laplata river dolphin

Of all the representatives of its family, this is the least specialized species in terms of structure and lifestyle. It can live both in rivers and in the seas. The body of males in length reaches approximately 155 cm, and the body of females is somewhat longer and can reach 170 cm. The body weight is small: from 28 to 35 kilograms. Cubs are born very small: approximately 45 cm in length. Thus, these are the smallest river dolphins. Where do Laplata dolphins live? They inhabit the mouth of the La Plata River and the coastal waters of Brazil, Uruguay and Argentina (between 30 and 45° S).

Their skin color is pale brown. The snout is very long, the number of teeth varies from 210 to 240. Various types of fish serve as food (herring, silver mullet, croaker fish), crayfish and cephalopods. The Laplata river dolphin is very sociable. It is known that individuals very willingly approach fishermen's boats and make contact with humans.

Dolphin is one of the most mysterious and interesting mammals living on our planet. It has been known since ancient times that these mammals can save drowning people and disperse the oculi that gather near a person.

In particular, dolphins love children. The main advantages of this species of mammals are their benevolence, sociability or the desire to establish any contact with a person. Today we will discuss the topic of where do dolphins live what they eat and how captivity weakens them.

How and where do dolphins live?

The habitat of dolphins can be called the places where they live. Their place of residence can be found in any area the globe. Here, everything will depend on the type of dolphin, some of them can only live in certain places. One type of dolphin is bottlenose dolphin or simply big dolphin.

Bottlenose dolphins are very common and can be observed in many places. Enough a large number of bottlenose dolphin is found in the waters of the Pacific, Indian and Atlantic Oceans, they can be seen in such seas as the Mediterranean, Red and, of course, Black. Places of residence different kind dolphins can be near the coastline, or right in the ocean shelf.

Migration of dolphins, which is associated with the search for an additional source of food, seems to be a frequent phenomenon. In the same case, if in any area there is enough food for these mammals, then they take root there for a very long time.

For example, consider bottlenose dolphins. They are almost always close to the coastline and rarely migrate. It depends on the amount of food near the shore, and most often it is there in great abundance. Bottlenose dolphins are exactly the kind of dolphins that many people are used to imagining. Bottlenose dolphins can often be seen near the coastline, and this type of dolphin can also be seen in almost all dolphinariums. Many people who do not think about this issue may get the impression that all dolphins live exactly like bottlenose dolphins, but this is an erroneous opinion.

In fact, many dolphins are subject to migration, especially those that live in the ocean shelf and have a completely different habitat. Most often, they travel in flocks and choose the right routes to find the right water temperature and enough food for themselves. Dolphins have the ability to swim hundreds of kilometers to find a source of food.

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Dolphin nutrition

Most often, dolphins look for fish of such breeds as food, such as:

• mackerel
• mullet
• cod
• herring, etc.

Sometimes, when there is no fish, they feed on squid. The diet of dolphins will depend entirely on what kind of fish is available in the area, as well as in what season they migrated here.

Dolphins can live not only in various seas and oceans, but also "their habitat", there may be captivity, i.e. various dolphinariums. Never before has man been presented with so many opportunities for open communication with these mammals. Here you can touch them, feed them and, of course, swim with them. But people, most often, simply do not understand how dolphins themselves suffer under these conditions, because many of them were caught, and thus torn out of natural environment a habitat.

Dolphins are smart enough and have high level intelligence, which is very difficult to develop in captivity. Scientists have long shown a lot of evidence that keeping dolphins in captivity causes them great suffering and greatly reduces their life expectancy. So, in the wild, a dolphin can live up to 50-60 years, and in captivity, its life expectancy will be reduced to 30 years.

Currently, many organizations have been created that promote the protection of dolphins and are ardent opponents of all existing dolphinariums.

Now you know how and where do dolphins live! We hope that the information provided was of interest to you.