River dolphins are in danger. River dolphin. Lifestyle and habitat of the river dolphin Freshwater dolphin

. family of river dolphins consists of Amazonian, Chinese, Gangetic and Lapland river dolphin. Unfortunately for everyone, Chinese river dolphins it was not possible to save: in 2012, the animals were given the status of "extinct".

Biologists believe that the reason for their extinction lies in poaching activities, the discharge of substances of chemical origin into water bodies, and violations of the natural ecosystem (the construction of dams, dams). Animals could not live in artificial conditions, so science does not know many of the nuances of their existence.

Description and features of the river dolphin

Amazon river dolphin a real record holder among members of the river dolphin family: the body weight of river inhabitants is from 98.5 to 207 kg, and the maximum body length is about 2.5 m.

Pictured is an Amazonian river dolphin

Due to the fact that animals can be painted in light and dark shades of gray, sky or even pink color they are also called white river dolphins and pink river dolphins.

The hue of the lower part (belly) is several tones lighter than the color of the body. The snout is elongated, slightly bent towards the bottom, in its shape resembles a beak, the forehead is rounded and steep. On the beak are hairs that have a rigid structure, which are designed to perform a tactile function. Eyes painted in yellow, and their diameter does not exceed 1.3 cm.

AT oral cavity 104 -132 teeth are located: those located in front are cone-shaped and designed for grasping prey, the back ones are stocky, to perform the function of chewing.

The fin on the back of the Amazonian river dolphin replaces the crest, the height of which ranges from 30 to 61 cm. The fins are large and wide. Animals are capable of jumping over 1 m high.

The Gangetic dolphin (susuk) is dark gray in color, gradually turning into gray on abdominal cavity. Length - 2-2.6 m, weight - 70-90 kg. The type of fins is not much different from Amazonian fins.

The snout is elongated, the approximate number of teeth is 29-33 pairs. Tiny eyes are not able to see, and perform a tactile function. Ghanaian dolphins are listed in Red under the status of "endangered species" because their population is very small.

In the photo, the river dolphin gang

The length of Laplata dolphins is 1.2 -1.75 m, weight - 25-61 kg. The length of the beak is approximately one sixth of the length of the body. The number of teeth is 210-240 pieces. The peculiarity of this species lies in its color, which has brown tint, and these are also characterized by hairs that fall out as they grow older. The fins look like triangles. The length of the fin located on the back is 7-10 cm.

river dolphins they have very poor eyesight, but, despite this, they are perfectly oriented in the reservoir thanks to their excellent hearing and echolocation abilities. The river dwellers cervical vertebrae not connected to each other, which allows them to turn their head at a right angle with respect to the body. Dolphins can reach speeds up to 18 km / h, in normal conditions they swim at a speed of 3-4 km/h.

The residence time under the water column ranges from 20 to 180 s. Among the sounds made, one can distinguish clicking, screeching in high tones, barking, whimpering. Sounds are used by dolphins to communicate with relatives, as well as to perform echolocation.

Lifestyle and habitat of the river dolphin

During the daytime river dolphins active, and with the onset of night they go to rest in areas of the reservoir, where the current speed is much less than in daytime places.

Where do river dolphins live?? Amazonian river dolphins are big rivers South America (Amazon, Orinoco), as well as their tributaries. They are also found in lakes and places near waterfalls (upstream or downstream).

During long droughts, when the water level in reservoirs drops significantly, they live in large rivers, but if there is plenty of water due to the rainy season, they can be found in narrow channels, or in the middle of a flooded forest or plain.

Ghanaian dolphins are common in deep rivers(Ganges, Hunli, Brahmaputra), as well as in the rivers of Pakistan, Nepal, Bangladesh. During the daytime, it dives to a depth of 3 meters, and under the cover of night it goes to a shallow depth in search of prey.

The habitats of the Laplata dolphins can be rivers and seas. They live near east coast South America, the mouth of La Plata. Basically, river dolphins live in pairs or small flocks, which consist of no more than a dozen individuals. In the case of abundant food availability, dolphins can create flocks several times larger.

Feeding the river dolphin

They feed on mollusks (, squid). The rivers in which dolphins live are very muddy, so the animals use echolocation to find food.

White river dolphins catch fish with their snout, and also use it as a tool for getting shellfish from the bottom of the reservoir. For prey they go to sections of the river with shallow depth.

They prefer to hunt alone or in small groups. Dolphins take the fish with their front teeth, and then move it to the back, which grind the head first and only after the animal swallows it, crush the rest. big booty torn apart, first biting off the head.

Reproduction and lifespan of the river dolphin

Puberty at river dolphins occurs at about 5 years of age. Pregnancy lasts for 11 months. After the baby is born, the female immediately pushes him out of the water so that he takes his first breath.

The body length of the cub is 75-85 cm, weight is about 7 kg, the body is painted in light grey colour. Shortly after the appearance of offspring, males return to the rivers, while females with offspring remain in place (in channels or valleys that were flooded after the water level rose).

Pictured is a baby river dolphin

Giving preference to such places, females protect offspring from lack of food, predators, as well as from aggressive actions from foreign males. The offspring stays close to the mother until about 3 years of age.

It is not uncommon for a female to become pregnant again without completing the lactation process. The break between matings can be from 5 to 25 months. live river dolphins no more than 16 - 24 years.

(China). It's a cetacean white color with a dorsal fin similar to a flag, which is why locals called it "baiji" (白鱀). scientific name kind Leipo means "forgotten"; specific vexillifer- "carrying the flag." In 2006, the expedition did not find this species. In August 2007, a Chinese man filmed a large white animal swimming in the Yangtze River.

Since 2017, the Extinct Animal Commission of China (CEC) has declared the species extinct.

For a long time this species belonged to the family Platanistidae; now separated into an independent family Lipotidae.

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Appearance

This is a light bluish-gray dolphin with a white belly. Body length 1.4-2.5 m, weight - 42-167 kg. Females are larger than males. The body is stocky. The neck is movable. Pectoral fins wide, as if chopped off at the end. The dorsal fin is of medium height, gently sloping, located slightly behind the middle of the body. Exposed from the water, it resembles a flag. The rostrum is very long, narrow, slightly curved upward, resembling a crane's beak. The blowhole is oval, shifted to the left. The lower jaw is white, with a white edge on the upper jaw. There are 2-3 pairs of teeth more than in the susuk (62-68 above and 64-72 below). Unlike other river dolphins, the eyes of the lake dolphin are greatly reduced, located high on the head; vision is very poor. By appearance closest to the Amazonian line.

Spreading

It was distributed in the central-eastern part of China in the river. Yangtze and the lower reaches of the river. Qiantang, as well as in the Dongting and Poyang lakes. Rarely observed below Nanjing; Only 1 time in Shanghai area. A special international expedition, which took place in November - December 2006, stated that the Chinese river dolphin, most likely, has completely disappeared [ ] .

Lifestyle

Ecology is practically not studied. They keep at the mouths of tributaries, near islands and in shallow water, in muddy water where vision is practically useless. Therefore, these dolphins see very poorly and rely mainly on echolocation. In the Yangtze, lake dolphins swim in shallow water only to hunt for fish. In terms of lifestyle, the river dolphin is close to inii. Daytime lifestyle, at night they rest in areas with slow flow. It feeds mainly on small fish, in particular eels and catfish, which it digs out of the bottom silt with its long beak, as well as molluscs. Dives for only 10-20 seconds. It crushes mollusk shells with its strong teeth, which have lateral outgrowths on wide roots. River dolphins are usually found in pairs, which sometimes merge into groups of 3-16 individuals, keeping in feeding places for 5-6 hours. A wounded dolphin makes a sound similar to the cry of a buffalo calf. noted seasonal migrations: in the lake. dongtinghu late autumn, in the rainy season, dolphins migrated from the lake up the rivers flowing into it; in the Yangtze in summer high water swam into small channels, returning to the main channel of the river in winter. The longest recorded migration was over 200 km. By nature, the river dolphin is secretive and shy.

reproduction

Reproduction is practically not studied. Apparently it is seasonal. Peak breeding occurs in February-April. Pregnancy is expected to last up to 11 months. The female brings one cub 80-90 cm long every 2 years. It is known that the cubs of the lake dolphin are very weak and practically do not know how to swim, so at first the female holds them with flippers, which was also observed in a number of other cetaceans. The duration of lactation is unknown; Dolphins reach sexual maturity between 3 and 8 years. Lifespan is unknown.

population status

The Chinese river dolphin is one of the rarest mammals on Earth. Since 1996, its status in the International Red Book is "species in critical state" ( Critically Endangered). Until 1900, its number was estimated at 3000-5000 individuals; in 1980 - at 400; in 1990, 200. In 2007, Chinese river dolphins were officially declared extinct. [ ]

According to paleontological excavations, river dolphins migrated to the Yangtze from

The dolphin is a representative of the suborder of toothed whales, the order of cetaceans, the dolphin family (Delphinidae). The graceful body of the dolphin has a spindle-shaped streamlined shape, which allows these mammals to quickly cut through the water surface. The speed of the dolphin reaches 50 km/h.

Humans and Dolphins

People have known about the extraordinary mind and quick wit of dolphins for a long time. These charming animals rescue people from ships in distress, preventing them from drowning. You could even say that dolphins are the smartest animals on the planet. Many trainers believe that the intelligence of dolphins can be equated to a human, these animals behave so intelligently and unusually.

There is a joke about dolphins, which says that if a person had not overtaken the dolphins and had not climbed down from the tree before, they would come out of the water and now would be the kings of nature, replacing us.

Dolphin is smart, kind, beautiful, he is an excellent student, analyzes, remembers.

Dolphins are directly related to formidable inhabitants oceans, killer whales and. There are about 50 species of dolphins. These include the porpoise, black dolphin, gray dolphin, white-faced dolphin, Atlantic white-sided dolphin.

The most popular bottlenose dolphin ( big dolphin), which people basically have in mind when talking about meetings with representatives of this species. They are well studied and tamed. Bottlenose dolphins are filmed in films, they participate in programs for the rehabilitation of children suffering from various neurological ailments.

Dolphin - description and photos. What does a dolphin look like?

A dolphin is not a fish, but a mammal. Common to all species is an elongated streamlined body, which is crowned with a small dolphin head with a beak-shaped mouth. Each jaw contains 80-100 small conical teeth. The dolphin's teeth are slightly tilted inwards. The transition between the muzzle and the frontal part is well defined. Almost all members of the dolphin class have a prominent dorsal fin. The skin is supple and smooth to the touch. The length of the dolphin can reach 4.5 meters depending on the species.

Dolphins in the water move very easily, they practically do not feel its resistance due to special fatty secretions on the skin that facilitate gliding. Interestingly, the dolphin's skin is quickly erased from the friction of water. Therefore, in the deep skin layers they have a significant supply of regenerating cells. The dolphin constantly sheds, changing up to 25 layers of skin per day!

The eyes of dolphins are small, vision is poor. This is due to the fact that animals practically do not use them for hunting. The nostrils are transformed into a blowhole located on the crown of the head.

How do dolphins breathe?

Whales and dolphins are related and can stay under water for a long time without surfacing. The drawbar is closed during such periods. But, like other cetaceans, dolphins still need air underwater and periodically rise to the surface to breathe.

Do dolphins have ears?

Dolphins have no ears. But that doesn't mean they don't have hearing. There is! True, it functions differently from other mammals. Sounds are perceived by the inner ear, and the air cushions located in the frontal part serve as resonators. But these animals are fluent in echolocation. They accurately determine the location and dimensions of the object by the reflected sound, and by the wavelength - the distance to it.

How Do Dolphins Sleep?

Dolphins also have another interesting physiological feature A: They never sleep. Animals hang in the water column, periodically rising to the surface for breathing. During rest, they are able to alternately turn off either the left or the right hemisphere of the brain, that is, only one half of the dolphin's brain sleeps, while the other is awake.

Where do dolphins live?

The habitat of the dolphin is exclusively water bodies. The dolphin lives in almost all places on our planet, with the exception of the Arctic and Antarctic regions. Dolphins live in the sea, in the ocean, as well as in large freshwater rivers(Amazonian river dolphin). These mammals love space and move freely over long distances.

Dolphin language

Dolphins are animals social, live in packs, in which there can be from 10 to 100 (sometimes more) individuals, fighting off enemies with common efforts. Inside the pack, there is practically no competition or fights between them; fellow tribesmen coexist peacefully with each other. Dolphins communicate using sounds and signals. Dolphin language extraordinarily varied. The "talk" of these mammals includes clicking, whistling, barking, and chirping. The dolphin voice spectrum extends from the lowest frequencies to ultrasonic. Moreover, they can combine simple sounds into words and sentences, passing information to each other.

What do dolphins eat?

The diet of dolphins includes only fish, preference is given to anchovies. The method of hunting used by animals is also interesting. A flock of dolphins finds a school of fish and with special sounds forces it to huddle into a dense group. As a result of this hunting most of the school becomes prey for dolphins. This feature is often used when attacking frightened fish from the air. There are known facts when dolphins helped fishermen by driving a joint to them in the net.

Sharks and dolphins

An interesting fact is that dolphins live in symbiosis. They often hunt together without showing any aggression towards each other.

Dolphin species

There are 17 genera in the dolphin family. Most interesting varieties dolphins:

• White-bellied dolphin (black dolphin, Chilean dolphin) ( Cephalorhynchus eutropia)

lives exclusively on the coast of Chile. An animal with a rather modest size - the length of the stocky and rather thick body of this cetacean does not exceed 170 cm. The back and sides of the white-bellied dolphin are gray, while the throat, belly area and parts of the flippers adjacent to the body are absolutely white. The flippers and dorsal fin of the white-bellied dolphin are smaller than those of other dolphin species. This type close to extinction, protected by the Chilean authorities.

• Common Dolphin ( common dolphin) (Delphinus delphis)

The length of a marine animal often reaches 2.4 meters, the weight of a dolphin varies between 60-80 kilograms. In the back area, an ordinary dolphin is painted dark blue or almost black, the belly is white, and a spectacular yellowish-gray stripe runs along the light sides. This species of dolphins lives in the waters of the Mediterranean and Black Seas, feels at ease in the Atlantic and Pacific Oceans. There is a common dolphin on east coast South America, along the coasts of New Zealand and South Africa, in the seas of Japan and Korea.

• white-faced dolphin ( Lagenorhynchus albirostris)

a large representative of cetaceans with a body length reaching 3 meters and weighing up to 275 kg. Distinctive feature The white-faced dolphin has a very light, sometimes snow-white muzzle. The habitat of this mammal includes the waters of the North Atlantic, the coast of Portugal and Turkey. The dolphin feeds on fish such as navaga, flounder, herring, whiting, as well as mollusks and crustaceans.

• Large-toothed dolphin ( Steno bredanensis)

The body length of this marine mammal 2-2.6 meters, weight varies from 90 to 155 kg. Height dorsal fin is 18-28 cm. The color of the dolphin is dominated by gray, over which whitish spots are “scattered”. This species of dolphin is common off the coast of Brazil, in the Gulf of Mexico and California, lives in warm waters Caribbean and Red Seas.

• bottlenose dolphin (large dolphin or bottlenose dolphin) ( Tursiops truncatus)

The length of the animal can vary from 2.3 to 3.6 meters, and weight from 150 to 300 kg. The body color of the bottlenose dolphin depends on the habitat, but basically the species has a dark brown upper part body and grayish-white belly. Sometimes there is a weakly pronounced pattern in the form of fuzzy stripes or spots on the sides. The bottlenose dolphin lives in the Mediterranean, Red, Baltic and Black Seas, and is often found in the Pacific Ocean along the coasts of Japan, Argentina and New Zealand.

• Broad-faced dolphin (beakless dolphin) ( Peponocephala electra)

common in the waters of countries with tropical climate, especially mass populations live along the coast of the Hawaiian Islands. The torpedo-shaped, light gray body of the animal is crowned with a cone-shaped dark gray head. The length of a mammal often reaches 3 meters, and an adult individual weighs more than 200 kg.

• Chinese dolphin (sousa chinensis)

This representative of the genus of humpback dolphins lives in the waters along the coast. South-East Asia, but migrates during the breeding season, therefore it is found in bays, quiet sea lagoons and even rivers washing Australia and the countries of South Africa. The length of the animal can be 2-3.5 meters with a weight of 150-230 kg. Surprisingly, although dolphins are born completely black, as they grow, the body color changes first to light gray, with slightly pinkish spots, and adults become almost white. The Chinese dolphin feeds on fish and shellfish.

• Irrawaddy dolphin ( Orcaella brevirostris)

A distinctive feature of this species of dolphins is the complete absence of a beak on the muzzle and a flexible neck, which received mobility due to several skin and muscle folds behind the head. The color of the body of the Irrawaddy dolphin can be either light gray with a blue tint or dark gray, while the belly of the animal is always a tone lighter. In length it aquatic mammal reaches 1.5-2.8 meters with a weight of 115-145 kg. The habitat of the dolphin covers the waters of warm indian ocean, starting from the Bay of Bengal and up to the northern coast of Australia.

• Cruciform Dolphin ( Lagenorhynchus cruciger)

lives exclusively in the waters of the Antarctic and subantarctic. The color of the dolphin is black and white, less often - dark gray. A spectacular white marking, covering the sides of the mammal, stretches to its muzzle, framing the eye area. The second mark runs along the back of the body, intersecting with the first and forming a pattern in the form hourglass. An adult cruciform dolphin has a body length of about 2 meters in length, the weight of a dolphin varies between 90-120 kilograms.

• Killer whale (killer whale) ( Orcinus orca)

a mammal that belongs to the dolphin family, a genus of killer whales. The male killer whale has a length of about 10 meters and a weight of around 8 tons. Females are smaller: their length reaches 8.7 meters. Pectoral flippers of killer whales have a wide oval shape. Killer whale teeth are quite long - up to 13 cm in length. The sides and back of the mammal are black, the throat is white, and on the belly is white stripe. There are white spots above the eyes. Sometimes there are completely black or white individuals in the waters Pacific Ocean. The killer whale lives in all waters of the oceans, except for the Sea of ​​Azov, the Black Sea, the Laptev Sea and the East Siberian Sea.

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 occurrence. 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.

Video plot

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" can 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 been given 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.

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 are primitive features 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 they 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 goes out of it into 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.