Dolphins have always evoked only pleasant associations in people, because these amazing animals are unusually intelligent and very beautiful. Everyone knows that they live in water, are playful and even save people. But is the dolphin a fish or a mammal? We will tell you about this.
In many ways, a dolphin resembles a fish: it lives in water, does not go out onto land, it has a streamlined body and several fins. In addition, if you compare him, for example, with a shark, then in their appearance you can find a lot in common. Still, the dolphin is a mammal, and here's why:
All representatives of the dolphin family belong to the order of cetaceans - mammals that have adapted to life in the water. In this regard, the fundamental difference between a dolphin and a fish is the absence of gills. Like most land animals, it breathes with its lungs, swallowing air through a hole in its head. Therefore, to replenish oxygen reserves, he has to regularly float to the surface.
Other significant differences are the way of breeding and feeding of offspring. The female dolphin usually carries only 1 cub, while her pregnancy lasts from 10 to 16 months (the duration depends on the species to which she belongs). In the first seconds after the birth of the baby dolphin, the mother pushes him to the surface so that he takes his first independent breath. Fish do not behave like that, even their viviparous representatives.
The very name of the class "mammals", to which dolphins belong, suggests that these animals feed on milk. And, indeed, the first year of life, the mother feeds her cub with breast milk, injecting it directly into the mouth. Only by the age of one year, dolphins begin to feed on fish, catching it on their own.
The difference in body temperatures of these animals also speaks in favor of the fact that the dolphin is not a fish. If most fish have the same temperature as the surrounding water, then dolphins, like all mammals, are. Accordingly, their body temperature is higher, and fat reserves distributed throughout the body help them survive in cold water.
In fairness, it must be said that there are fish in the world that can increase body temperature by 10-13 degrees. These are tuna and llama sharks. But this ability does not extend to their entire body: the blood in the gills and their heart remain the same as the temperature of the water around them. That, of course, distinguishes them from the always warm-blooded dolphins.
All these facts clearly prove that dolphins are mammals. In addition, scientists consider them to be the closest relatives, including hippos, which definitely have nothing to do with fish.
Dolphins are marine mammals that belong to the suborder toothed whales. They are found in the seas and oceans, as well as rivers that have access to the sea. They usually feed on crustaceans, molluscs, fish, and some do not disdain sea turtles and birds.
Where do dolphins live?
The dolphin's habitat 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.
Description
Dolphins range in length from one and a half to ten meters. The smallest dolphin in the world is Maui, which lives near New Zealand: the length of the female does not exceed 1.7 meters. A white-faced dolphin about three meters long is considered a large inhabitant of the deep sea. The largest representative is the killer whale: the length of the males reaches ten meters.
It is worth noting that males are usually ten to twenty centimeters longer than females (with the exception of killer whale dolphins - here the difference is about two meters). They weigh on average from one hundred and fifty to three hundred kilograms, a killer whale - about a ton.
The backs of sea dolphins are gray, blue, dark brown, black and even pink (albino) colors. The front of the head can be either solid color or white (for example, a white-faced dolphin has a white beak and front part of the forehead).
In some species, the mouth is rounded in front, and there is no beak-like mouth. In others - small in size, the head ends with an elongated mouth in the form of a flattened "beak", and the mouth has such a shape that it seems to people watching them that they are always smiling, and therefore they often have an irresistible desire to swim with dolphins. At the same time, the impression is not spoiled even by a huge number of teeth of the same conical shape - dolphins have about two hundred of them.
Due to their elongated body and smooth, elastic skin, these animals almost do not feel the resistance of water during movement. Thanks to this, they are able to move very quickly (the average speed of a dolphin is 40 km / h), dive to a depth of about one hundred meters, jump out of the water nine meters high and five meters long.
Another unique feature of these marine mammals is that almost all types of dolphins (with the exception of the Amazonian river dolphin and a few other species) see well both under water and above the surface. They have this ability due to the structure of the retina, one part of which is responsible for the image in water, the other - above its surface.
Since whales and dolphins are relatives, like all representatives of cetaceans, they are quite capable of staying under water for a long period. But, they still need oxygen, so they constantly float to the surface, showing a blue muzzle and replenishing air reserves through the blowhole, which overlaps under water. Even during sleep, the animal is fifty centimeters from the surface and, without waking up, floats out every half a minute.
Dolphin species
There are 17 genera in the dolphin family. The most interesting species of dolphins:
- White-bellied dolphin (black dolphin, Chilean dolphin) (lat.Cephalorhynchus eutropia) lives exclusively on the coast of Chile. An animal of 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 completely white. The fins and dorsal fin of the white-bellied dolphin are smaller than those of other dolphin species. This species is close to extinction, protected by the Chilean authorities.
- Common dolphin (common dolphin) (Latin Delphinus delphis). The length of the sea animal often reaches 2.4 meters, the weight of the dolphin varies between 60-80 kilograms. In the area of the back, the common dolphin is colored dark blue or almost black, the belly is white, and along the light sides there is a spectacular strip of a yellowish-gray hue. This species of dolphins lives in the Mediterranean and Black Seas, and feels at ease in the Atlantic and Pacific Oceans. The common dolphin is found on the east coast of South America, along the shores of New Zealand and South Africa, in the seas of Japan and Korea.
- White-faced dolphin (lat.Lagenorhynchus albirostris) - a large representative of cetaceans with a body length of up to 3 meters and a mass of up to 275 kg. A distinctive feature of the white-faced dolphin is 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 such fish as capelin, navaga, flounder, herring, cod, whiting, as well as molluscs and crustaceans.
- Large-toothed dolphin (Latin Steno bredanensis). The body length of this marine mammal is 2-2.6 meters, weight varies from 90 to 155 kg. The height of the dorsal fin is 18-28 cm. The coloration of the dolphin is dominated by gray, over which whitish spots are "scattered". This dolphin species is common off the coast of Brazil, in the Gulfs of Mexico and California, and lives in the warm waters of the Caribbean and Red Seas.
- Bottlenose dolphin (big dolphin or bottle-nosed dolphin) (Latin Tursiops truncatus). The length of the animal can vary from 2.3 to 3.6 meters, and the weight from 150 to 300 kg. The color of the bottlenose dolphin's body depends on the habitat, but mainly the species has a dark brown upper body and a grayish-white belly. Sometimes on the sides there is a weakly pronounced pattern in the form of indistinct stripes or spots. 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.
- Wide-faced dolphin (beaked dolphin) (lat.Peponocephala electra) common in the waters of countries with tropical climates, especially large populations live along the coast of the Hawaiian Islands. The torpedo-shaped, light gray body of the animal is crowned with a cone-shaped head of dark gray color. The length of a mammal often reaches 3 meters, and an adult weighs more than 200 kg.
- Chinese dolphin (lat.Sousa chinensis). This representative of the genus of humpback dolphins lives in the waters along the coast of Southeast 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 and weighs 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 the adults become almost white. The Chinese dolphin feeds on fish and shellfish.
- Irrawaddy dolphin (Latin Orcaella brevirostris). A distinctive feature of this type of dolphin is the complete absence of a beak on the face and a flexible neck, which received mobility due to several skin and muscle folds behind the head. The body color of the Irrawaddy dolphin can be either light gray with a blue tint or dark gray, while the animal's belly is always a tone lighter. In length, this aquatic mammal reaches 1.5-2.8 meters and weighs 115-145 kg. The dolphin's habitat covers the waters of the warm Indian Ocean, from the Bay of Bengal all the way to the northern coast of Australia.
- Cruciform dolphin (lat.Lagenorhynchus cruciger) lives exclusively in the waters of the Antarctic and subantarctic. The dolphin is black and white, less often dark gray. A striking white mark, covering the sides of the mammal, extends to its muzzle, framing the eye area. The second mark runs longitudinally to the back of the body, intersecting with the first and forming an hourglass pattern. An adult cruciform dolphin has a body length of about 2 meters in length, the weight of a dolphin varies between 90-120 kilograms.
- Orca (killer whale) (Latin Orcinus orca)- a mammal that belongs to the dolphin family, the genus of killer whales. The male killer whale has a length of about 10 meters and a weight of about 8 tons. Females are smaller: their length reaches 8.7 meters. Breast flippers of killer whales have a wide oval shape. The teeth of killer whales are quite long - up to 13 cm in length. The sides and back of the mammal are black, the throat is white, and there is a white stripe on the belly. White spots are located above the eyes. Sometimes completely black or white individuals are found in the waters of the Pacific Ocean. The killer whale lives in all waters of the world's oceans, except for the Sea of Azov, the Black Sea, the Laptev Sea and the East Siberian Sea.
Dolphin speed riddle
In 1936, British zoologist Sir James Gray drew attention to the tremendous speed (up to 37 km / h, according to his data) that dolphins manage to develop. Having made the necessary calculations, Gray showed that, according to the laws of hydrodynamics, it is impossible to achieve such a high speed with the muscle strength that dolphins have. This puzzle is called the Gray Paradox. The search for its solution, to one degree or another, continues to this day. At different times, various research teams have put forward various explanations for the phenomenal speed of dolphins, but there is still no unambiguous and universally recognized answer to this question.
The ability to regenerate
Dolphins have an incredible ability to heal themselves. In the event of any wound - even a large one - they do not bleed or die from infection, as one might expect. Instead, their flesh begins to regenerate at a rapid rate, so that after just a few weeks, there are almost no visible scars at the site of a deep wound, such as from a shark's teeth. Interestingly, the behavior of injured animals is practically the same as usual. This suggests that the nervous system of dolphins is capable of blocking pain in critical situations.
Why don't dolphins freeze underwater?
Finally, let's find out why dolphins, being warm-blooded, do not freeze in the water. Their body temperature is 36.6 degrees. In the northern seas, animals need to keep warm. Water, which conducts heat up to twenty-five times more efficiently than air, allows you to freeze much faster than in air.
Why do dolphins do such miracles ?! This is due to the large layer of fat under the skin. They can control their circulation and metabolism. This makes it possible to maintain a normal body temperature, according to Wikipedia.
How do dolphins breathe?
Whales and dolphins are relatives and can stay under water for a long time without surfacing. The breath is closed during such periods. But, like other cetaceans, dolphins still need air under water and occasionally float to the surface to breathe.
How do dolphins sleep?
Dolphins have another interesting physiological feature: they never sleep. Animals hang in the water column, periodically rising to the surface for breathing. During rest, they are able to turn off alternately the left and the right hemisphere of the brain, that is, only one half of the dolphin's brain is sleeping, and the second is awake.
How are they born?
Do you know how dolphins are born? For about a year, the bottlenose dolphin bears a baby. It is born with its tail first. The eyes of the baby are immediately open, and the senses are perfectly developed. Moreover, a barely born dolphin already has sufficient coordination to follow in the footsteps of its mother, who helps to rise to the surface. This is followed by the first breath in the life of a baby dolphin. Such a trusting relationship between a baby dolphin and its mother lasts approximately 3 to 8 years.
Dolphins and humans: who is smarter?
When dolphins began to be studied and trained in the middle of the last century, the first results of this work seemed so unusual, and even amazing (much talked about, wrote and made films about) that gradually a legend was formed about the unusually high intelligence of dolphins; it was often possible to hear that they were no more stupid than a person, only their mind was different.
The brain of an adult dolphin weighs about 1700 grams, and that of a person - 1400. A dolphin has twice as many convolutions in the cerebral cortex. At the same time, there are relatively few neurons in a cubic millimeter of its substance (less than in the brain of primates).
Research on the behavior and physiology of the dolphin brain has been controversial. Some put their learning ability roughly on the level of a dog and show that dolphins are very far from chimpanzees. Studies of dolphins' communication methods, on the contrary, pushes to the conclusion that we have not yet come close to understanding this life form in natural conditions and it is simply incorrect to compare the level of intelligence of dolphins and chimpanzees.
One property of the dolphin brain is completely unique: it never really sleeps. Sleep - alternately - either the left or the right hemispheres of the brain. The dolphin needs to surface from time to time to breathe. At night, the waking halves of the brain take turns responsible for this.
Dolphin communication
Dolphin tongues can be divided into 2 groups:
- Sign language(language of the body) - various poses, jumps, turns, different ways of swimming, signs given by the tail, head, fins.
- The language of sounds(proper language) - sound signaling, expressed in the form of sound impulses and ultrasound. Examples of such sounds include: twittering, buzzing, squealing, grinding, clicking, smacking, creaking, clapping, squeaking, roaring, screaming, screaming, croaking, whistling.
The most expressive are the whistles, which dolphins have 32 kinds... Each of them can mean a certain phrase (pain signals, alarms, greetings and a call to me, etc.). Scientists have studied dolphins' whistle using the Zipf method and obtained the same slope coefficient as in human languages, that is, carrying information. Recently, dolphins have been found to have about 180 communication signs, who are trying to systematize, compiling a dictionary of communication of these mammals. However, despite numerous studies, it has not yet been possible to fully decipher the language of dolphins.
Dolphin names
Each dolphin has its own name, which it responds to when its relatives address it. This conclusion was reached by American scientists, whose research results were published in the Bulletin of the US National Academy of Sciences (PNAS). Moreover, experts who conducted their experiments in the US state of Florida found that the name is given to the dolphin at birth and represents a characteristic whistle.
Scientists have caught 14 light gray bottlenose dolphins with nets in the wild and recorded various sounds made by these mammals in the process of their communication with each other. Then, with the help of a computer, the "names" were extracted from the records. When a name was “played” for a flock, a specific specimen responded to it. The dolphin's "name" is a characteristic whistle, the average duration of which is 0.9 seconds
Official recognition
The Indian government recently removed dolphins from the animal population and designated them as "non-human." Thus, India became the first country to recognize the presence of intelligence and self-awareness in dolphins. In this regard, the Ministry of Environment and Forestry of India has banned all performances with dolphins and called for the respect of their special rights.
- There are 43 species of dolphins. 38 of them are marine, the rest are river inhabitants.
- It turns out that in ancient times, dolphins were land, and only later adapted to life in the water. Their fins resemble legs. So our sea friends might once have been land wolves.
- Dolphin images were carved in the deserted city of Petra, Jordan. Petra was founded as early as 312 BC. This gives reason to consider dolphins one of the most ancient animals.
- Dolphins are the only animals whose babies are born tail first. Otherwise, the cub may drown.
- A dolphin can drown if a tablespoon of water gets into its lungs. By comparison, a person needs two tablespoons to choke.
- Dolphins breathe through an adapted nose, which is located at the top of their head.
- Dolphins can see with sound, they send signals that travel long distances and are reflected off objects. This allows the animals to assess the distance to an object, its shape, density, and texture.
- Dolphins are superior to bats in their sonar capabilities.
- During sleep, dolphins stay on the surface of the water to be able to breathe. For control, one half of the animal's brain is always awake.
- "The Cove" won an Oscar for documentary on dolphin treatment in Japan. The film explores the theme of cruelty to dolphins and the high risk of mercury poisoning when eating dolphins.
- It is assumed that hundreds of years ago, dolphins did not have this ability to echolocate. This is a quality acquired with evolution.
- Dolphins do not use their 100 teeth to chew food. With their help, they catch fish, which they swallow whole. Dolphins don't even have chewing muscles!
- In ancient Greece, dolphins were called sacred fish. Killing a dolphin was considered sacrilege.
- Scientists have found that dolphins give themselves names. Each of the individuals has its own personal whistle.
- Breathing in these animals is not an automatic process, as in humans. The dolphin's brain signals when to breathe.
Almost all types of dolphins live in warm salt waters. There are 47 of them in total. These are the indigenous inhabitants of the seas and oceans. But in addition to marine mammals, there are also river dolphins, which are a separate family, which includes 6 species. These animals live in the rivers of India, China and South America. Their habitat is the Ganges, Indus and Brahmaputra in India. In China, they can be found in Lake Dongtinghuv, and in South America, they have chosen for themselves the Amazon, Orinoco and La Plata.
River dolphins are inferior in size and weight to their marine relatives and have a more primitive brain structure. The body length of these animals usually ranges from 1.5 to 2.5 meters, and the weight is not less than 40 kg, but also does not exceed 120 kg. The bodies of river animals are usually brown or almost white in color, sometimes dark carcasses are also sometimes encountered. Vision in these mammals is very weak or almost completely absent. The most characteristic difference from sea brethren is the cervical vertebrae. They are not fused into a single bone like in ocean dwellers, but separated like in land mammals.
Dolphins are mostly heat-loving animals. Only certain species like cool waters. These include striped dolphin... It is common in the North Pacific. It can be found off the coast of Sakhalin and the Kuriles, in the waters adjacent to California and Japan. This mammal reaches a length of 2.2-2.3 meters. The average weight is 140 kg. The maximum weight of males can range from 180 kg. Females are not lighter than 100 kg.
It is a very lively, fast and energetic dolphin. He can often be seen from the sides of ships. Swift graceful bodies with dark narrow stripes on the sides can accompany the vessel for a very long time. Moreover, the animals swim not only in a parallel course, but also easily overtake the floating vehicle, cross its path and perform various jumps and pirouettes.
The closest brother of the striped dolphin is common dolphin... Along with the shores of Canada, England, Korea and Japan, he also loves the warm waters of the Mediterranean and Black Seas. It can also be found off the coast of Australia, where the animal feels quite comfortable. The dolphin is very graceful and the fastest of all its marine cousins. In water, he easily develops a speed of 60-70 km / h. Likes to jump. Their height reaches 5 meters.
The color of the squirrel is very beautiful. The back is black with a greenish tint, and the belly is white. The eyes are edged with black circles. The dolphin reaches a maximum length of 2.4 meters with an average length of 2 meters. The weight of the animal is about 110 kg. The common dolphin has a high dorsal fin: its height is 80 cm. These mammals live in large flocks and are very fond of frolicking at the water surface.
Dolphin species would have lost a lot if there was no such representative among them as bottlenose dolphin... It is a large mammal, reaching a length of 2.3-3.2 meters. Sometimes you come across bottlenose dolphins of more impressive size with a body length of 3.6 meters. The mass of this dolphin is usually in the range of 300 kg. The maximum weight reaches 400 kg. The habitat of this animal extends to all temperate and warm waters of the World Ocean. The bottlenose dolphin can be found in the Black and Mediterranean Seas, in the Indian Ocean, in the Atlantic and in the Pacific, where he is very fond of the waters washing the shores of Southeast Asia and Australia.
The body color of different individuals is not the same, but differs in shade. Mostly, a dark brown back and a gray belly predominate. Animals with a white belly come across. Sometimes you can find a representative of the species in which the whole body has a solid gray color. The speed that the bottlenose dolphin develops in the water is 40 km / h. He has developed a very good and friendly relationship with the man. The dolphin lends itself well to training and even masters some of the words spoken by people. This species most often appears in dolphinariums, striking the audience with its skill.
Without exception, all types of dolphins have one characteristic feature. Sometimes they are in bulk washed ashore and perished... Experts explain this phenomenon in different ways. The prevailing point of view is that such suicides are the result of the work of certain brain centers of the animal, directly related to the generation of high-frequency sounds. Sometimes the established frequency of vibrations of the earth's surface resonates as a result of exposure to external vibrational sources. These can be wind, tremors of the earth's crust, or the work of ship's radars.
The altered frequency signal can match the sound that a wounded dolphin makes. It’s like a person to whom sometimes the howl of a storm outside the window looks like a crying child. Let us recall AS Pushkin: “She will howl like a beast, then she will cry like a child.” The nearby flock perceives such a signal as a call for help. She quickly rushes to the coast, is thrown ashore and dies. Similar actions are observed in all marine mammals that do not abandon their fellows in trouble (for example, the same whales), which once again confirms the correctness of this version.
Dolphins are some of the most extraordinary inhabitants of the sea. According to legend, they were companions of the ancient gods. Scientists are trying to talk to them in the truest sense of the word. It is already an indisputable fact that communication with these marine mammals is curative, a whole line of medical rehabilitation is used where possible.
No one really could explain the friendliness of the dolphin towards humans. It seems that a person floating in the water awakens in them a kind of maternal feelings. There are countless eyewitness accounts of how dolphins rescued drowning people. But in the mouth of this mammal there is a real palisade of teeth, which look quite frightening. However, it is with these teeth that the dolphin can pick up a drowning person and pull him to the surface, and do this extremely gently and affectionately. By the way, bottlenose dolphins and other brothers in the oceans use their formidable "weapon" exclusively to grab gape fish and do not bother chewing food. They swallow the prey whole.
Some scientists believe that dolphins have long sought to communicate with us. They often approach people and ships unexpectedly. They jump, move, whistle, as if they want to tell us something.
There is an insurmountable difference between us. This is the frequency range of audio signals. We, that is, Homo sapiens, exchange news, lecture or give notations in a frequency band not exceeding 20 kilohertz. Gifted musicians are able to distinguish up to 40. And for dolphins, a completely normal level of perception at a frequency of up to 300 kilohertz. They use sound signals of a wide variety of frequencies. The ultrasounds they emit serve primarily for echolocation. In the language of dolphins, whistles are very important, which are used in different situations, expressing a whole range of feelings. They are very diverse in their characteristics - each dolphin has its own manner of speech. Therefore, by the nature of the whistle, the dolphins in the group recognize each other.
It was the possession of ultrasound that at one time attracted the military, who used trained dolphins to search for underwater objects, detect and destroy scuba divers-saboteurs. Underwater living "torpedoes" are capable of detecting objects at a distance of up to a kilometer with their ultrasonic sonars, and not only in the dark, but also under a layer of silt.
Californian researchers analyzed the communication structure of dolphins. We learned an amazing circumstance. It turned out that children of the sea have about the same number of levels of organization of sounds as humans: six. Sound, syllable, word, phrase, paragraph, context. In a person, semantic meaning arises from the word. And from what step there is mutual understanding among dolphins is still unknown. However, scientists came to the conclusion that in terms of complexity, the organization of sound signals in humans and dolphins is almost the same. And they also have their own dialects - something like human foreign languages.
The meaning of many signals is still not clear, but researchers managed to decipher some sounds. For example, flapping jaws is a threat signal, loud squealing is severe pain, yapping is waiting for food, and a sound such as barking is a conversation between males and females during the mating season. Dolphins are good at imitating extraneous sounds. Some scientists have no doubt that over time, dolphins can be taught meaningful human speech.
Until recently, scientists seriously believed that dolphins do not sleep at all or almost do not sleep at all, otherwise they may choke (or suffocate) without atmospheric air. However, a more thorough study of the habits of neighbors on the planet made it possible to find out that they still stay in the arms of Morpheus, only in a very peculiar way. During sleep, they turn off one half of the brain and the opposite eye. The other half of the brain is awake at the same time, not forgetting to give the dolphin commands to rise to the surface in time to take a breath of air. And the second eye remains alert in case of predators or other danger. This kind of sleep takes about 6-7 hours a day. Dolphins usually sleep half a meter from the surface of the water, dropping their tail down.
There are many notable parallels between the two species, Homo sapiens and Orcinus orca. They, like us, can eat anyone, but no one attacks them. Their lifespan is about the same as that of people, they grow up at the same age, are very sociable, live in families. Dolphins, like us, breathe air; at birth, females feed their young with milk.
In terms of intelligence, by the way, dolphins are mammals that have the largest brain volume relative to its height. On average, a dolphin's brain is 20-30 percent larger than a human's. So, if in the process of evolution they would have turned out to be "land" earthlings, it is still unknown who would become the "king of nature."
Perhaps it is thanks to their intelligence that dolphins live in water, although it seems that once, in incomprehensible antiquity, the earthly firmament was a familiar element for them. If we look at the dolphin's skeleton, we can see that the bones of the long fingers are still preserved in the upper fins, these are the last traces of being on the ground. But the hands gradually turned into fins, thanks to which the sea inhabitants swim very quickly. Maybe in time immemorial, the ancestors of modern dolphins realized that it was simply more convenient for them to live in water: you can move in any of three directions, you do not need a roof over your head and clothes, and tools are also useless. So why complicate things?
Dolphins have long been one of the most beloved water animals for humans. And this is not surprising! After all, dolphins are the most peaceful, intelligent and friendly creatures on the planet! When we talk about dolphins, we always imagine trained cetaceans performing acrobatic stunts before our eyes. However, there are countries that are categorically against dolphinariums, believing that these smart creatures should not live outside the natural environment, because the number of dolphins is significantly decreasing from year to year. And only the human factor is to blame for this.
A bit of history
It is assumed that the sperm whale, whale, dolphin, including the sea pig, descended from the same ancestors - mammals that inhabited the earth millions of years ago, but were not purely land animals, but rather liked to hunt and live in the water. These are mesonychids - omnivorous creatures with hooves, like those of horses and cows, with a predatory, wolf-like appearance. According to rough estimates, Mesonychids lived for more than sixty million years, and they inhabited the modern continent of Asia, part of the Mediterranean Sea (in ancient times it was the Tethys Sea). These animals, most likely, ate any medium-sized aquatic animals and any fish that then inhabited numerous swamps off the coast.
And due to the fact that the mesonichids spent most of their life in any body of water, their appearance gradually began to develop in breadth, flow around, the limbs turned into fins, while the hair on the skin began to disappear, and subcutaneous fat developed and increased under it. To make it easier for animals to breathe, the nostrils ceased to fulfill their original function: in the process of evolution they became a vital organ for the animal, since creatures could breathe through them, and all thanks to their displacement up the head.
Even if for a long time it was believed that the ancestors of cetaceans, including dolphins, were indeed mesonychids, nevertheless, most of all they "borrowed" from hippos, and this is proved by numerous molecular studies. Dolphins are not just descendants of these artiodactyls, they are deeply similar and are part of their group. Until now, hippos and hippos live mainly in water, on land they are only a couple of hours to eat. That is why scientists suggest that hippos are one of the evolutionary branches of cetaceans. It's just that the whales went further than the hippos, they generally abandoned life on land and completely switched to life in the water.
And if it seems strange to you that hippos and hooves are related to legless cetaceans, then we want to give another version of taxonomy, for example, land animals with 4 legs, which evolved from fish. Simply, we should not be surprised that long since our civilization appeared, the evolution of dolphins proceeded so rapidly.
Description of dolphins
Dolphins are large waterfowl that breathe air, in contrast to fish, which breathe through the gills. Sea dolphins are in the water all 24 hours, and here they give birth to little dolphins. Since the female feeds her babies herself, therefore they are warm-blooded creatures, mammals.
Unlike their relatives - whales, dolphins are more beautiful creatures. Except for the sharp teeth in their intelligent and friendly gaze, one cannot find any sinister intrigues. So, an adult dolphin can be 2.5 meters long, weighs only three hundred kilograms. Whereas it can be nine meters long and weigh eight tons. Males are always larger than females by at least 20 centimeters. They have more than eighty teeth. The color of the trunk and fins is black or gray, while the tummy is white.
The largest organ The cetacean dolphin has a brain that is amazingly awake all the time the dolphin sleeps. The brain allows the animal to breathe all the time, even when it is asleep: this way the dolphin will not drown, because the supply of oxygen for cetaceans is very important for life.
Scientists have called dolphin skin a natural miracle. This is their wealth! When dolphins calmly extinguish water turbulence, when the body needs to slow down a little.
It is interesting!
Submarine designers have been looking closely at how dolphins swim for a long time. Thanks to the dolphins, the designers managed to create artificial skin for the submarine.
Dolphins: what they eat and how they hunt
Shellfish, various types of fish and other aquatic animals are the food of the dolphin. Interestingly, dolphins can eat a lot of fish in a day. Dolphins hunt fish in schools, and each of its members can eat up to thirty kilograms... All this is due to the fact that dolphins are animals that, at too low temperature regimes of ocean or sea water (below zero degrees Celsius), must always maintain their own temperature in order to be optimal. And it helps warm-blooded dolphins in this thick subcutaneous fat, which is constantly replenished due to a huge amount of food. That is why dolphins are always on the move, hunting, and only at night allow themselves a little rest.
A flock of dolphins can very quickly catch up with a fish flock, because in the sea these animals are aces. If dolphins are already near the beach, they instantly form half rings around the fish in order to push their future food to shallow water, and eat there. As soon as the dolphins take fish shoals captive, they do not immediately rush at them, and then continue to keep them in a circle so that they do not swim away, and each member of the flock could have lunch or dinner with their favorite food.
To see the dolphins, it is enough to find a school of fish. Similarly, these cetaceans will live where there are many, many fish. In summer, dolphins can be met in full in Azov, when mullet and anchovy move to the sea to feed. Dolphins also swim close to the Caucasian shores in early autumn, when the fish begin to migrate in herds.
As you have already noticed, you can rarely see one dolphin in the ocean, since these animals are very friendly, they like to live in flocks, hunt together and even jump beautifully and perform their tricks in harmony with the dolphins, together with their comrades. Whatever it was, but dolphins never got along with killer whales. Also, there are still poachers who hunt these friendly earthly creatures. Despite everything, dolphins trust people and even know how to communicate not only with each other, but also with other animals. They will never leave their comrades in trouble. And in case of severe danger, they can even help a person. How many legends and stories exist in the world about dolphins saving lives. Some even watched as dolphins pushed boats to the shores, which were blown away by the winds.
Dolphin breeding
Unlike other inhabitants of the aquatic world, dolphins are the only ones that are born with tails, not heads. And this is so. Loving mothers do not leave their cubs even after two or three years after birth.
It is interesting!
Dolphins are incredibly sensual and compassionate animals. The little dolphin, even after it becomes completely independent, an adult male or female, never, under any circumstances, abandons its parents.
And dolphins feel great affection and love not only for their own brethren, but even for whales, other animals (they don't like killer whales) and people. After the female and the male have cubs, they never part, even after having numerous cubs. Who, if not dolphins, know how to love their cubs, gently and lovingly deal with them, teach, take them hunting with them, so that soon the children themselves will know how to hunt fish.
It is interesting!
If dolphins hunt and feel danger, they lead their children from behind, but if there are no external threats, dolphin cubs calmly swim ahead of their parents. Interestingly, after the young, the females swim, and then the males are the protectors.
Relationships with people
Since each dolphin with his fellow tribesmen and whales lives in peace and harmony, then he behaves accordingly. The sense of help in these animals is especially developed. They will never leave a sick dolphin to die, they will save even a drowning man at sea, if, by a lucky chance, they find themselves nearby. Dolphins will hear a man's cry for help far away, since their hearing is very developed, as well as the brain section.
The fact is that dolphins spend all their time in the water, which is why their vision is impaired (weak water transparency). Then, as the hearing is excellently developed. The dolphin uses active location - the hearing is able to analyze the echo that occurs when it makes characteristic sounds from any objects surrounding the animal. Based on this, the echo tells the dolphin what shape, how long the objects around him are, what they are made of, in general, what they are. As you can see, hearing completely helps to fulfill a visual role for the dolphin, which does not prevent this peace-loving creature from feeling full in such a complex world.
It's easy for humans to tame a dolphin. Fortunately, like a dog, an animal is easy and simple to train. One has only to lure the dolphin with a delicious fish. He will do any flip for the public. Although dolphins have one flaw, they can forget any trick very quickly if a person forgets to feed him in time.
Why do we all treat dolphins differently than other animals. Looking at these cute and funny creatures, you forget about how huge these animals are, and how, despite their size, they are the only cetaceans that can be safely classified as the best "friends".
Dolphins, like grandmothers on a bench overly curious... They swim up to the person with interest, flirt with him, throw a ball, and even smile, although few people notice this. They are so arranged, to smile at us, to laugh with us. Well, we cannot call the face of a dolphin a muzzle, the smile on the face - cheerful and friendly - that's what attracts us to them!
Dolphins love us, we love them. But there are ... heartless people who, for the sake of profit, forget about humanity and kill these peaceful creatures. In Japan, dolphin hunting is like a drink! They don't even think to talk about sympathy for dolphins. On other continents, dolphins are housed in dolphinariums for the entertainment of the people. In cramped conditions, in which they do not live longer than five years (for comparison, in nature, dolphins live up to fifty years).
It is interesting!
The Indian state became the fourth in the world to ban the construction of dolphinariums. The first to ban these cetaceans in captivity were Asian Chile, Costa Rica, and also in Hungary. For Indians, dolphins are not the same as a person who also has the right to freedom and life in nature.
Dolphin therapy
The history of the great friendship between sea dolphins and humans goes back a long way, even before scientists began to call these animals dolphins. Researchers of cetacean body language have concluded that they have developed verbal communication skills just like humans. If a mentally ill child, autistic, spends a lot of time with dolphins and "communicate" with them, then this has a beneficial effect on him. The child begins to smile, laugh. The British spoke about this back in the 70s of the last century. Subsequently, dolphin therapy began to be actively used to treat not only mental and neurological diseases, but also many physical ones. Swimming with dolphins together is beneficial, it can relieve stress, severe headaches, neuralgia and even rheumatism.
Behavioral anomalies
All of you, probably on the news or on the Internet, observed such a picture when the beaches are full of unauthorized dolphins. Often they themselves are thrown away, because they are very sick, injured, or poisoned. Dolphins clearly hear sounds from the shore, which are very similar to the screams for calling for help from their fellows. Therefore, upon hearing such a cry, dolphins rush to the shore to help, and are often trapped.
