Where is the river dolphin found, how does the freshwater dolphin live. Where can you see dolphins in Russia in their natural habitat? Which of the river dolphins is the largest

18.10.2019

(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

where do dolphins live

what continent does dnlfin live on
In the sea
in the seas, the Black Sea, the Caspian Sea, the Barents Sea, the Kara Sea, the Sea of Okhotsk, the Laptev Sea, the Sea of Japan, the White Sea, the North Sea.
in the ground
The question, to put it mildly, is childish….
Suborder
Toothed whales (Odontoceti)
Family
Dolphin
(Delphinidae)
47 kinds

Cetaceans of small size. Body length 1.1-10 m (in the family, small dolphins with a body length of 1.1-4 m, medium-4.1-7 m and large 7.1-10 m can be distinguished). Males are usually larger than females. Sexual dimorphism can also manifest itself in other characters - the shape and size of the dorsal fin, the shape of the pectoral fins. Caudal fin with a deep notch between the lobes. Most representatives have a large dorsal(sometimes it is absent), located approximately in the middle of the body. The slit of the blowhole, located on the crown, is horseshoe-shaped and faces forward with its ends.
There are no furrows on the throat. The "beak" is well developed, long or completely absent. The color of the body is varied: one-color (gray, black), dark above and light below, or with various light stripes or spots.
The skull is asymmetrical. The zygomatic and temporal bones are poorly developed in the skull. The proximal parts of the facial bones do not form ridges. The pterygoid and nasal bones are relatively small in size. There are pre- and postorbital processes. The symphysis of the lower jaw usually does not exceed 1/3 of its length. Rostrum long or short. The width of the lower and upper jaws is approximately the same.
Dental formula 0-65/2-58
The teeth are homodont, in most dolphins they are small in size, sometimes large and massive. The top ones go in between the bottom ones.
The cervical vertebrae fuse into various combinations.
Widespread in almost all seas globe. Some are distributed very widely, almost all over the world (dolphin-barreled dolphin, killer whales), others are more local.
Mobile animals leading a pack lifestyle. The food is varied. Among the representatives of the family, ichthyophages, teutophages, teutoichthyophages and sarcophagi can be distinguished.
Family
river dolphins
(Platanistidae)
6 types

Gangetic dolphin or susuk (Platanista gangetica)
Indian dolphin (Platanista indi)
Amazonian inia or bowto (Inia geoffresis)
Bolivian river dolphin (Inia boliviensis)
Chinese lake dolphin (Lipotes vexillifer)
La Plata dolphin (Pontoporia blainvillei)
The most ancient family of modern toothed dolphins. It originated in the Miocene and spread widely in the ocean, but was forced out by competitors and enemies into the rivers. River dolphins are characterized by primitive features inherited from their ancestors (squalodonts) - a very elongated (relatively shorter in young than in adults), a narrow snout and a long mandibular symphysis.
Members of this family are relatively small. . Body length 1.5-2.9 m. Weight up to 40-123 kg. Females are somewhat larger than males. The "beak" is thin and long (1/6-1/7 body length), sharply separated from the frontal protrusion. The frontal prominence is sometimes sloping or somewhat more convex. The Amazonian and Gangetic dolphins have a cervical interception. The pectoral fins are wide and short, fan-shaped. The dorsal fin is small in the Amazonian and Gangetic dolphins and relatively large in the La Plata and lacustrine dolphins. Body color varies greatly from brown or blackish to almost white. Vision is poorly developed or completely absent, for example, in Gangetic dolphins, in whose eyes there is no lens.
In the brain, the number of convolutions is less than in other dolphins.
They live in rivers, closer to deltas, and La Platsky - in the sea.
in the seas and oceans!
Species of the dolphin family (Delphinidae) live in all open seas and sometimes enter the mouths of large rivers. Representatives of the family of freshwater, or river, dolphins (Platanistidae) have a much more limited distribution. For the most part they inhabit inland fresh waters, although some of them can penetrate into brackish estuaries and even into the coastal zones of the seas. The Stenidae family includes species that live in the seas, fresh waters or both of these environments
Bottlenose dolphins (Tursiops) .. Of the species of this genus, the most famous is the Atlantic, or simply bottlenose dolphin (T. truncatus), widespread in warm waters around the world.
Common Dolphin ( Delphinus delphis) from the genus common dolphins one of the most common representatives of the family in the Mediterranean Sea. White flanks inhabit warm and temperate seas around the world. They are usually divided into three subspecies: one in the Atlantic and, possibly, Indian Oceans, another in the Pacific and the third in the Black Sea. Independent, albeit closely related forms are sometimes isolated for South Africa, Japan and the Red Sea
Short-headed dolphins (Lagenorhynchus) are represented by several species: depending on the classification used, their number can reach up to six. Representatives of this genus usually inhabit colder waters than other dolphins, and some species even reach pack ice. One of them, the Pacific striped dolphin (L. obliquidens), is regularly exhibited in several aquariums and is remarkable for its ability to jump over a high-hanging crossbar.
Continued here: http://www.krugosvet.ru/articles/02/1000203/1000203a2.htm
What Do Dolphins Can Do?
Dolphins possess some skills that were previously attributed only to humans and higher apes. Among them are self-identification with a reflection in a mirror, a developed system of signal communication, abstract thinking, the ability to learn (do not confuse with training!) And transfer learned skills between generations.
Probably in the ocean

The Chinese river (lake) dolphin is one of the the rarest species mammals of our planet. Life cycle this amazing view animal is very short.

For the first time they started talking about it in 1918, found in Dongting Lake. And already in 2006, not finding a single individual, river dolphins were declared extinct. A year later, according to an eyewitness and according to the video footage, it was possible to fix one mammal in the very long river our mainland Yangtze, where in last years these dolphins have found their final home. Previously, he lived not only in these waters, but also inhabited the expanses of the Tsentang River, Poyang Lake and Dongting Lake.

The appearance of the Chinese dolphin

An elegant mammal of light gray color, the belly of which shimmers with silvery-white hues. The stocky bodies of dolphins do not exceed two and a half meters, and body weight can range from forty-two to one hundred and seventy kilograms.

Moreover, males are noticeably smaller than their chosen ones. A feature of this species is a narrow and very long rostrum, resembling a crane's beak. Has thirty-four top and thirty-six bottom pairs of teeth. Characterized by poor eyesight.
Lifestyle

The river dolphin is an animal with a "beak".

It chooses for itself habitats in the mouths of tributaries, near islands and in shallow waters. It navigates in muddy water thanks to echo. During the day, dolphins are active, but spend the night in places with a slow current. The Chinese river dolphin hunts mainly for mollusks and small fish, but does not refuse from and.

He himself has no enemies in nature. It was possible to see dolphins in pairs, and sometimes in a group of up to sixteen individuals. It can dive for a short time, only up to twenty seconds. For this type of summer time migration to small channels was characteristic, and in winter they returned to their original places.

The river dolphin is a rare animal.

Due to the fact that this species is poorly understood, unfortunately, the process of reproduction, life expectancy and much more will remain a mystery to us.

To study this unique look attempts have been made to keep the lake dolphin in captivity. Unfortunately, even those close to natural conditions did not lead to success.

. family of river dolphins consists of the 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 major 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 mating can be from 5 to 25 months. live river dolphins no more than 16 - 24 years.

Among the variety of dolphins inhabiting warm waters of our planet, there is a group of freshwater or river dolphins. Different types these mammals live in the Amazon, the rivers and lakes of China, in the rivers of India. Representatives of the river dolphin family are the most ancient among their relatives. It is believed that they have a more primitive structure compared to sea dolphins. There are fewer convolutions in their brains, the dorsal fin is usually absent, and the head has a characteristic elongated narrow beak, like theirs. ancient ancestor- squalodont. But the special structure of the cervical vertebrae allows river dolphins to turn their heads in relation to the body up to 90º, which their marine relatives are deprived of.

One of the species of river dolphins is the Gangetic dolphin, or susuk. Some researchers identify two certain types: Gangetic dolphin and small Gangetic dolphin. He lives in the Ganges, Indus, Brahmaputra and their tributaries. Gangetic dolphin has light gray color and a long beak, slightly thickening towards the end, and its dorsal fin is practically not developed. But this species is interesting in that it is practically blind. Gangetic dolphins have rather small eyes, which lack a lens, but have receptors that can capture sunlight. That is, they are able to capture only the source of light, everything else is hardly distinguishable for them. But if you think about it, this is not surprising. After all, these dolphins live in muddy waters Ganges, in which the concentration of suspended solids is high. Therefore, even with good eyesight, it's hard to see anything there. That's what nature has decided acute vision These dolphins don't care. Similar evolutionary metamorphoses can be observed, for example, in moles, which also lost their sight as unnecessary. How then do Gangetic dolphins find food and communicate with each other? Everything is simple. Although these river mammals have a more primitive body structure, they have developed acoustic abilities, like their marine relatives. The ability to echolocation helps them to easily navigate in space, hunt and find their own kind.

Unfortunately, in recent decades, the number of representatives of this amazing species has been declining. According to rough estimates, their number is only a few thousand individuals. To date, this dolphin is categorized as an endangered species. But this is not due to the hunting of these animals (it is almost never carried out), but due to changes in their traditional habitats. The fact is that due to the construction of hydroelectric power stations on the rivers of the region, the habitat of these dolphins was divided into several sections. So, for example, the Ganges dolphins are divided into four isolated populations after the construction of the dams. International group scientists are developing measures to build bypass channels for dolphins to remedy the situation. Therefore, it can be hoped that this species will not be threatened with extinction in the near future.