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Secondary water

About fifty live in the oceans different types dolphins. All of them, together with the whales, make up a detachment cetaceans (Cetacea). Dolphins and whales are secondary aquatic animals (their ancestors once lived on land). Only external form bodies and those that live in the water, cetaceans resemble fish. In all other respects, they are real mammals. They are warm-blooded, breathe with lungs, give birth to live young and feed them with milk.

At least 70 million years ago, the terrestrial ancestors of cetaceans moved to live in the water and eventually completely lost contact with the land. Blood tests, remains of the pelvis, hind limbs and single hairs on the muzzle confirmed that cetaceans and ungulates are relatives. But what made the dolphin ancestor change his terrestrial existence to a water one 65 million years ago, and who, in fact, was he? It can be assumed that the whole thing is some kind of cosmic cataclysms that touched the Earth and forced animals to seek salvation in the water. After all, it was at this time that the dinosaurs suddenly disappeared from the Earth.

no sense of smell

The only studied group of animals that have no (or almost no) sense of smell are toothed whales (dolphins, killer whales and sperm whales). They have neither olfactory bulbs nor olfactory nerves. And most of their olfactory receptors (about 80%) don't work. This is not surprising - after all, their ancestors lived on land and lost their "water" receptors. And when the whales fully adapted to life in the water, they ceased to be interested in “airy” smells, like fish.

primitive whales

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

freshwater whale

In the Indus River basin, paleontologists have discovered the skull of a fossil whale that lived 50 million years ago. Studies have established that the animal's hearing organs were not adapted for life in the water and, therefore, such individuals are the land ancestors of modern whales.

Cetaceans are homogeneous

Cytogenetically, in terms of chromosome composition, which includes 42-44 chromosomes, cetaceans are more homogeneous than other orders of mammals associated with aquatic environment. This gives reason to believe that the living suborders of cetaceans are genetically close and descended from the same root.

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

The fountain of the whale does not shoot straight up.

The sperm whale has a single opening for breathing - the “nostril”, “blowhole”. The fountain of water from it does not hit straight up, like in other species of whales, but at an angle. The humpback whale launches 3-8 fountains with an interval of 4-15 s.

narwhal horn

In male narwhals (Monodon monoceros), a very long, up to three meters long, straight thin "horn" sticks out in front of the head! In fact, this is not a horn, but a tooth, just greatly enlarged. It grows on the left side of the jaw and, surprisingly, is twisted, and always counterclockwise. There is also a tooth on the right side of the jaw, which is also directed forward, but it is hidden in the soft tissues of the gums, although sometimes it grows into a second tusk ... comes from his head and is nothing more than an overgrown tooth. Sailors of antiquity identified the narwhal with the unicorn.

Surprisingly, the purpose of this tooth is still unclear to the end. It is known that it is very strong due to the helical torsion. Some believe that this tooth serves as a tournament weapon for males during the mating season. Others claim that it helps animals break through ice. But all these conjectures, apparently, are far from the truth.

Teeth and throat

On the lower jaw sperm whale (Physetser catodon)- 36-60 teeth, and on the top there are none at all.

Mouth length bowhead whale (Balaena mysticetus)- 6.5 m, width - 4 m.

Fangs wrap around the jaw

The adult male Layard's whale whale (Mesoplodon layardii) has boar-like fangs that grow from the lower jaw and can be up to one and a half meters long. They curl around the upper jaw and prevent the whale from opening its throat, so the whale has to strain the krill that comes in with the water.

Whale with movable neck

White whale, (Delphinapterus leucas), white color the whale, 5-6 m long, has no dorsal fin. It has a movable neck, allowing the head to move freely independently of the body.

Distribution of most cetacean species
...very wide, aided by the absence of pronounced barriers. Nevertheless, whales live in local (local) herds, and even during very distant migrations, as a rule, they do not cross the equator. There are cold-loving species living in polar and subpolar waters (beluga whales, narwhals, bowhead whales), thermophilic (Bride's minke), tropical and subtropical (many small dolphins, pygmy sperm whales).

Growth of an adult whale

About 30 meters. If such a whale is placed on its head near high-rise building, then the tail will be about the 10th floor.

The longest fin

… at humpback whale a 7.7 m long fin can grow. This is longer than that of other whale species. Latin name for this whale Megaptera, means "long-winged".

Dolphins are also whales
Toothed whales (Odontoceti). have one breathing hole. Their food is fish and krill. These include killer whales, pilot whales, sperm whales. Dolphins are also small toothed whales.

Whale bones are soft and liquid
Whales are able to reach enormous sizes because their weight is supported by water. Unlike land mammals, which have strong bones, the bones of whales are soft and porous, they store a supply of oily fat.

migrate in groups

As a result of adaptation to seasonal conditions of nutrition and reproduction, several biological groups of cetaceans have formed. Species of one group make strictly regular migrations within the Northern or Southern Hemisphere; for the winter baleen whales, part of the beaked and sperm whales go to low latitudes for childbirth, and in the summer they go to temperate and cold waters. It is easier to work up fat in the Arctic and Antarctic, since there are 10-20 times more planktonic organisms than in the tropics. Species of another group also move over considerable distances, but less regularly and with violation of seasonal periods (killer whales, pilot whales, partly sei whales, narwhals, etc.). Types of the third group in mind relatively sedentary life; their migrations take place within a small water area (bottle dolphins, river dolphins, gray dolphins, etc.).

Echolocation in whales evolved 39 million years ago

Over the past 47 million years, there have been two qualitative leaps in the evolution of cetaceans, accompanied by an increase in brain size. The first such jump took place 39 million years ago (the emergence of echolocation "in service" with whales is identified with it), the second - about 15 million.

Communicate at low frequencies
Whales, like elephants, mainly communicate through low-frequency noises that are inaudible to the human ear, in order to communicate with each other at a distance of several kilometers.

The brain of a fin whale


The brain of a northern fin whale (herring whale) Balaenoptera physalus weighs 7 kg, an elephant - 5 kg, a human - 1,400 g, a horse - 500 g, a cow - 350 g, a pig - 150 g, a dog - 100 g, a gibbon - 89 g, a cat - 32 g. hedgehog brain mass - 3.2 g.

Dolphins are catching up with humans in terms of brain size

If we compare the volume of the brain and its changes in the course of evolution, then dolphins are not far from humans. The brain of a 300-pound (about 135 kilograms) dolphin weighs 1,700 grams, while that of a human weighing 65-70 kg. - 1400 gr. The human brain is about 7 times larger than that of other animals of similar sizes - in dolphins this figure is 5. The dolphin has twice as many convolutions in the cerebral cortex, although in a cubic millimeter of its substance there are relatively few neurons in any case less than in primate brain. In general, the brains of primates (which include humans) and cetaceans are at approximately the same stage of development, although this development followed completely different paths. However, who knows, maybe dolphins will be able to catch up and overtake primates in terms of intelligence.

Half of the brain rests during sleep

The cerebral hemispheres are highly developed, in the cortex of which structures are concentrated that perform the most important psychological functions. During sleep, one half of the brain is awake in dolphins and whales, while the other half is at rest.

The neck of cetaceans is very short.
The neck is very short, since the seven cervical vertebrae common to mammals are greatly shortened and fused into one or more plates, the total length of which does not exceed 15 cm.

Whalebone
Baleen whales are the largest animals in the world. They get their food with the help of a filtering apparatus - a whalebone that fits in their mouths. Therefore, the head of baleen whales is very large, it occupies 1/3-1/5 of the body of the animal, there are no teeth. The teeth of baleen whales are replaced by long fringed horny plates (whalebone) hanging from the upper jaw and forming a filter for straining small crustaceans and fish from the water. This suborder includes minke whales, as well as blue, humpback, pygmy, smooth, bowhead and other whales.

The most baleen whale in the world
- Greenland (Balaena mysticetus) - can grow a mustache up to 5.8 meters long.

The largest mammal

Blue whale Balaenoptera musculus- most large mammal not only today, but also ever lived on Earth. It is larger than even the largest dinosaur. The largest whale, a female, measured 34 m in length. The heaviest known whale weighed over 190 tons, the weight being hypothesized based on the weighing of its remains. This corresponds to the mass of 30 elephants or 150 bulls. This animal is larger than even giant dinosaurs. The whale can reach enormous sizes, since its limbs do not have to support the weight of the body: in the water it is, as it were, in weightlessness.

The loudest mammal
- it blue whale. It can produce sounds with a volume of 188dB, which can be heard at a distance of 850 km.

When females are larger than males

Males are usually somewhat larger than females and more robustly built. But in baleen whales, on the contrary, females are noticeably larger than males.

Northern blue whale heart

(Balaenoptera musculus) weighs 600-700 kg, a hundred times more than its brain.

sea ​​singers

The beluga whale emits a variety of sound signals: whistling, screeching, muffled groans, chirping, screaming, gnashing, piercing scream, roaring (hence the proverb "roars like a beluga"). Beluga whales were nicknamed “sea singers” for their “melodious singing”, and the mournful cries of humpback whales became a symbolic plea for the preservation of their kind. Noteworthy are the long (up to half an hour!) and melodic songs of humpback whales in warm waters, to some extent characteristic of other species of baleen whales. Though exact value whale songs have not yet been discovered, among humpback whales they are associated with mating season when males call females. Songs can be performed either alone or in a choir.

Dolphins love to "talk"
- their chirping and whistling can be heard under water.

When Dolphins Talk to Humans
The dolphin brain provides dolphins with verbal communication with each other and in the future will allow you to meaningfully talk with a person. The difficulty of verbal communication between a human and a dolphin is explained by the fact that a human hears only a small part of the signals of the second: after all, the frequency perception range of dolphins is 10 times higher than that of humans.

sperm whale with sonar cannon

Sperm whales have sonars, which use them to search for deep-sea squid aggregations. The sonar of the sperm whale is a kind of long-range cannon ", having a length of up to 5 m and occupying almost a third of the body of the animal.

70 teeth

Dolphins have over 70 teeth.

sperm whale teeth
As in the annual layers of wood on a tree, by the number of alternating transparent and opaque stripes on the cut of the tooth, you can find out the age of the animal. The teeth of 12 adult sperm whales were examined. The whale's dentin (the substance that makes up the bulk of the tooth) has one or more bright bands. It turned out that in male sperm whales it is rare and looks transparent and homogeneous, while in females it has a complex structure. Along the bright stripe, stripes of different thickness are darker, denser than its main part. Comparing all these facts, the researchers came to the conclusion that the complex structure of the bright strip in the tooth of the female sperm whale is a kind of “mark”, it is associated with the birth of the cub and the period when the female feeds him with her milk (for sperm whales, this lasts 18 months) .

Can control blood pressure

Whales are able to control the volume of blood flowing to the heart and brain, which helps them avoid oxygen deprivation during deep dives.

Blue whale language
At the bottom of the mouth between the lower jaws lies a huge sac-like tongue; it weighs up to 3 tons (in blue whales) and half consists of fat. This is the mass of an adult African elephant.

Whales have hands and fingers
Whale embryos have limbs and even fingers, which are modified before birth.

Dolphins love physical contact.

Dolphins love physical contact - they caress each other with their fins.

The best diver

- sperm whale (Physeter catodon)- can dive for three kilometers and hold his breath for 2 hours and 18 minutes. This is the largest toothed whale: males reach 20 m, and females - 15 m.

When females are in the south and males are in the north
Male sperm whales are distributed over a larger area than females, migrate further than females and reach in the summer in the north. the Davis Strait, the Barents and Bering Seas, and in the south - Antarctica. Females live in harems, breed in the tropics and rarely venture outside subtropical zone. North of the equator, most harems spend their summers between 25 and 40 degrees N. sh., and winter - between 0 and 25 degrees N. sh. Bachelor migrating groups of male sperm whales do not take part in reproduction. They are formed after females expel extra males from shoals, leaving marks of their teeth on the exiles' skin. The remaining males fiercely fight among themselves for the place of the head of the harem and strike each other with massive heads, sometimes break their teeth and damage their jaws. In a harem, there are usually 10-15 females, sucklings and a large male. If harems are combined into a herd, then several males are kept with it.

Cetaceans have a sense of smell

Previously, it was believed that cetaceans lack a sense of smell. However, the anatomical study of toothed whales found special depressions in the oral cavity located at the root of the tongue, which perceive odors in the water.

At dolphins (Delphinae) almost no sense of smell.

Poor vision

Whales living underwater cannot boast of good eyesight. This is offset by excellent hearing and the ability to echolocate, which helps whales navigate and search for food.

Good hearing at low frequencies below 1 kHz

Behavioral data suggest that baleen whales (Mysticeti), including western gray whales, hear very well at low frequencies below 1 kHz. Baleen whales responded to sonar and other sounds at frequencies between 3 and 4 kHz. Some baleen whales respond to ultrasound up to 28 kHz, but do not respond to sounds above 36 kHz. In addition, baleen whales make sounds with frequencies up to 8 kHz. They can hear low frequency sounds (perhaps around 10 Hz) from sources many hundreds of kilometers away. Therefore, the hearing range of baleen whales, including western gray whales, can likely range from<1 до 8 кГц. Нарушение слуха может произойти в случае, когда кит подвергается воздействию звуков силой более 180 дБ относительно 1 мкПа.

Ears, eyes and nose

There are no external ears, but there is an ear canal that opens with a small hole in the skin and leads to the eardrum. The eyes are very small, adapted to life at sea. They are able to withstand high pressure when the animal is immersed to a great depth, large fatty tears stand out from the lacrimal ducts, which help to see more clearly in the water and protect the eyes from the effects of salt. Nostrils - one (in toothed whales) or two (in baleen whales)- located in the upper part of the head and form the so-called. blowhole. In cetaceans, unlike other mammals, the lungs are not connected to the oral cavity.

Vision and hearing of a dolphin
Spending its entire life in the water, the dolphin is forced to constantly rise to the surface to breathe. Therefore, his vision must be good enough both under water and in the air, and this is not easy, since the optical properties of air and water are completely different. On the other hand, no matter how good the dolphin's eyesight is, its capabilities are limited due to the low transparency of the water. Therefore, the dolphin receives basic information about the environment through hearing. At the same time, he uses an active location: he listens to the echo that occurs when the sounds he makes are reflected from surrounding objects. The echo gives him accurate information not only about the position of objects, but also about their size, shape, and material.

What can a dolphin see

Dolphins see well both under water and in the air. It is possible that such universality of dolphin vision is associated with the presence of two zones in their eye: on one of them, the optics of the eye provides a good image in water, and on the other, it is predominantly in the air. When a dolphin wants to see something underwater, it usually turns to the object sideways (with one eye), i.e. uses the posterior-lateral zone. And in order to see an object in the air, the dolphin is located with its nose towards it (looks with two eyes), i.e. uses the front zone. The visual acuity of dolphins is 8-14 ". This is worse than that of many terrestrial animals: for example, in humans and primates, visual acuity is about 1", and in cats 5-6 ". But for underwater conditions, where the transparency of the environment is low, this is quite enough This is also proved by observations of animals kept in aquariums: they know their trainers very well, they can make precise aimed jumps and, without a single miss, reach objects placed at high altitudes.

Blind-sighted Amazonian dolphin

The Amazonian dolphin (Inia geoffrensis) is an amazing animal that lives not in the seas, but in the rivers of South America. The water there is very muddy, almost opaque, and the eyes of the Amazonian dolphin have adapted to vision at a very short distance (you can’t see anything further anyway) and in low light (turbid water absorbs light strongly). This dolphin has only one zone, but not in the center of the retina, like in land animals, but in its lower part - the one that looks up. Only there, in the upper layer of water, is there enough light to see at least something. Accordingly, the visual acuity of the Amazonian dolphin is very low: 45 ". But great visual acuity is not needed if you look at objects that are only tens of centimeters away.

The hearing of a dolphin is almost a hundred times higher than that of a human.

The fact that the dolphin has an unusually developed hearing has been known for decades. The volumes of those parts of the brain that are in charge of auditory functions are tens (!) times larger than that of a person (despite the fact that the total volume of the brain is approximately the same). A dolphin is able to perceive frequencies of sound vibrations that are 10 times higher (up to 150 kHz) than a person (up to 15-18 kHz), and hear sounds whose power is 10-30 times lower than that of sounds accessible to human hearing. The hearing of a dolphin turned out to be not two or three or even ten times higher than that of a person, but dozens (almost a hundred) times. Human hearing allows you to distinguish time intervals from about one hundredth of a second (10 ms). Dolphins, on the other hand, distinguish intervals of ten-thousandths of a second (0.1-0.3 ms).

Accurate dolphin sonar

Dolphins possess the ability to create and perceive ultrasounds. Precise sonar makes it possible for them to detect objects the size of an acorn in water at a distance of up to 15 m. Thanks to echolocation, dolphins find food and avoid collisions with obstacles even in completely muddy water.

What Do Dolphins Can Do?
Dolphins possess some skills that were previously attributed only to humans and higher apes. Among them - identification of oneself with a reflection in a mirror, a developed system of signal communication, abstract thinking, the ability to learn (do not confuse with training!) And the transfer of learned skills between generations.

Hears a drop

A dolphin, enclosed in a large tank, will be able to hear and locate the splash of water poured out of a teaspoon.

smart dolphin

Professor A. Portman from Switzerland conducted research on the mental abilities of animals and found out that according to the results of the test, a person came out on top - 215 points, a dolphin was on the second - 190 points, and an elephant was the third winner. The monkey took only fourth place. The dolphin's cerebral cortex has twice as many convolutions. Isn't this what explains the amazing quick wits and incredible quickness of thinking of the dolphin? He is able to absorb the amount of knowledge 1.5 times more than people with you.

sexual fantasies

Dolphins have nothing to offer as an excuse for their perverted behavior: sometimes they try to get hold of sea turtles.

Dolphins play with children

In the Tsemess Bay, on the Black Sea, a dolphin appeared near the shore. He swam up to a group of bathing children and began to play with them. He allowed himself to be stroked and even to sit on him astride. Having cut enough, the dolphin retired back to the sea.

Dolphins rescue castaways Once a passenger ship was wrecked. Several people survived. None of them believed that they could survive. And when they saw a flock of sharks approaching them, they said goodbye to each other. But suddenly a miracle happened. A flock of dolphins rushed from the open sea, fearlessly dispersing a flock of sharks. And she helped people stay afloat until help arrived.

Dolphins rescue their
An even more striking incident occurred with the fishermen in the same place in the Black Sea. A flock of dolphins surrounded the launch and swam nearby, making sounds and clearly trying to attract the attention of people. The dolphins circled around the ship until people realized that the animals were worried about something. Following them, they found a captured dolphin. Having fought off the flock, he got tangled in a fishing net. The cub was rescued and released.

Member of the underwater expedition

The fate of the famous dolphin Tuffy, an honorary member of the American underwater expedition, is interesting. The dolphin worked as a postman and conductor, bringing appliances and tools. If one of the aquanauts swam too far into the sea and lost his bearings, Tuffy always came to the rescue and led the lost one to the house on a nylon leash. After such a brilliant debut, Tuffy was accepted into service at one of the US missile ranges. He searched the sea for the electronic devices of spent rocket stages. All equipment was crammed with miniature ultrasonic transmitters. The dolphin was in a hurry to their "call signs".

Dolphin Pilot
The dolphin Polorus Jack, so nicknamed by English sailors, has been guiding ships through the dangerous strait in New Zealand for 25 years as a real pilot.

Dolphins teach each other
Not so long ago, an absolutely amazing incident occurred in the marine aquarium in Miami. Several dolphins caught in the ocean were brought here for training. Not far from the recruits were already trained dolphins. They did not see each other. And yet, a conversation immediately began between them. All night long strange sounds and noises were heard from the pool. The unthinkable happened in the morning. The new dolphins immediately began to perform all the tricks that people intended to teach them. It seems that their brothers, who have long lived in the pool, told them about this.

Speed ​​over 50 km/h

At the age of 3 years, the dolphin becomes an adult. Their shiny bodies amaze with a perfectly streamlined shape, reminiscent of a drop or a torpedo. Dolphins move easily and quickly in the water. An adult dolphin is capable of reaching speeds of over 50 km/h.

big whale, sailing at a speed of 20 knots (37 km / h), "generates" energy of 520 liters. With.

Increase movement speed
Dolphins jump out of the water in order to increase their speed. It turns out that at a speed of 5 meters per second, a dolphin, jumping out of the water, increases it by another 3 meters. And this is important when hunting for fish.

rowing tail

Whales do not row with their fins; their tail provides them with swift movements. In water, the tail is the rudder and propeller. Whales drive their huge body forward with their tail, but the tail does not move from side to side, like in fish, but from bottom to top and back. This makes it possible to quickly sink and quickly rise to the surface.

Whales are excellent swimmers

The tail serves as a propeller and propels them forward, and the lateral fins give the body rotation and provide turns.

Swimming champions
tamed killer whales can reach a speed of 38 km / h, striped prodolphin (Stenella attenuata), large-browed [bridle] prodolphin Stenella frontalis- 43 km / h, and pilot whales, or ball-headed dolphins (Globicephala)- 49 km / h. The fastest whales can swim at a speed of 56 km/h. the usual speed of whales is not so high - the speed of movement for grazing belugas is only 1.5-2 km / h, and for frightened ones it increases to 22 km / h. At travel speed humpback whales inferior to real minke whales, making 13-15, and when injured, 25 km / h. Grazing blue whale moves at a speed of 11-15 km / h, and a frightened one develops a speed of 33-40 km / h. But he can move so fast only for a few minutes, because at such a speed his huge body must develop power up to 368 kW.

The furthest swimmer

The gray whale (Eschrichtius gibbosus) swims up to 20,000 kilometers a year.

How often do whales breathe

At an average speed, the whales emerge every 1-1.5 minutes, but are able to remain under water for a maximum of a quarter of an hour. In the enclosures, respiratory pauses varied from 5 to 140 sec. humpback whales usually immersed for 3-6 minutes, up to a maximum of half an hour. In shallow places under water they stay less than in deep ones.

Hold your breath for the longest time
... among animals is capable bottlenose whale (Hyperoodon). He may not breathe for 120 minutes, that is, 2 hours. For example, on average, a person holds his breath for only 1 minute, and a trained diver (pearl fisher) - for 2.5 minutes.

Physics of dolphin skin

The surface of the dolphin's skin reduces friction and helps them glide through the water quickly and unobstructed. The streamlined bodies of dolphins help them reduce water pressure on their bodies and reduce friction. The top layer of dolphin skin, which is renewed on average in two hours, also plays an important role in increasing the speed of their movements. The "softness" and "waviness" of the skin helps to reduce friction. The constant renewal of the skin reduces friction by breaking up the tiny whirlpools of water that form around the dolphin and can slow it down.

Special properties of the skin
The outer layer - about 1.5 mm - is extremely elastic. The inner layer with a thickness of about 4 mm consists of a dense fabric. Interestingly, the inner part of the outer layer is permeated with many passages and tubes filled with a soft fatty substance. By the way, artificial skin for submarines is similar in quality to dolphin skin.

Thick layer of fat
The body of cetaceans is covered with smooth, shiny skin that makes it easier to glide in the water. Under the skin is a layer of adipose tissue (blubber) with a thickness of 2.5 to 30 cm. Fat protects the body from hypothermia and helps to retain water in the body, which would otherwise diffuse into the environment; body temperature is maintained at about 35 ° C. Animals do not need a coat, since fat provides sufficient thermal insulation, however, in the embryonic stages and in adults, sparse hair can be found on the snout.

Have a thick layer of fat under the skin

A mighty layer of fat has developed under the skin as a protection against cold and an energy reserve in case of hunger strikes. The thickest layer of subcutaneous fat lies on the most passive parts of the body - on the belly and between the pectoral fins. Beneath the layer of fat in the posterior third of the body lie two mammary glands with one nipple each. The nipples are hidden in two longitudinal skin pockets located below on the sides of the urogenital fissure, and protrude outward only in lactating females.

Skin covered in shells

freshwater dolphin

In 1918, an unknown species of freshwater dolphin was discovered in Tongting Lake, located in Central China and 1,000 kilometers from the mouth of the Yangtze. It was a cetacean, completely white, its "body length was two and a half meters, it had an elongated snout, reminiscent of both a crane's beak and a flagpole. That is why the locals called it "peishi", which means "poor flag." And the American zoologist Gerrit S. Miller dubbed it the Chinese lake dolphin (Lipotes vexillifer).

Oral knowledge is passed on from generation to generation

Dolphins, according to the American neurophysiologist John Lilly, have knowledge and collective memory. But since they could not develop a written language, as they are deprived of hands, their life experience is transmitted to younger relatives and descendants orally.

hairless mammals
The elastic and smooth skin of cetaceans is devoid of hair, sweat and sebaceous glands. Only individual hairs stay on the muzzle and chin of newborn dolphins for several days and then fall out, while in baleen whales they remain throughout their lives, acting as tactile bristles.

cetacean coloration

Body coloration in some species acquires a masking value, while in others it acquires a signal-identification value. Catchy, bright white spots on the body are important for relatives so as not to jump on them during the rut, games, and swift swimming in flocks. In many cetaceans, the color changes with age: some, like the beluga whale, are born dark, then become gray, blue, and finally white; others, like the spotted dolphin, are born uniformly gray or dark, and then become covered with spots; still others, like bottlenose or beaked beakers, “turn gray” from the head in old age.
As a rare occurrence in cetaceans, albinism and melanism occur. In the first case, an albino is born to parents with a normal non-white color - pure white with red eyes. In the future, this offspring gives birth to a normally colored cub, as evidenced by the exhibits - an albino porpoise and its matured dark embryo, exhibited in the museum of the Novorossiysk Biological Station. In the second case, a completely black cub is born to non-black parents - a melanist, which subsequently gives birth to a melanist too.

nostrils

They open on the crown with one hole (in toothed whales) or two (in baleen whales). This hole is called a blowhole. The blowhole opens with muscles only for the moment of a short respiratory act - a continuous exhalation-inhalation, and the rest of the time, called a respiratory pause, is tightly closed. The respiratory act is regulated by resurfacing reflexes. The locking device can be roughly likened to a rubber stopper, which, only for a moment, stretches, lets air through when exhaling and inhaling, and then immediately retracts, automatically closing the nostril. Therefore, water, if only an animal. does not absorb it at will, cannot enter the respiratory tract through the blowhole. This is also excluded from the side of the mouth, since the larynx is designed so that the airway is separated from the food: neither water nor food from the mouth enters the windpipe even at the moment of breathing. However, dolphins can be trained to suck water into the nasal canal through the blowhole and throw it out 1-2 m in a strong stream or in the form of a spray fountain.

Dolphins breathe
With a sudden jump, he throws the body out of the water in order to take a breath. The muzzle of the dolphin is extended into a narrow beak, the nostrils are merged into one "blowhole", from which the animal can release a fountain of spray 1-1.5 m high. 4

fountain of whales

- this is a column of condensed vapor Before immersion in water, the lungs are filled with air, which, while the whale remains under water, heats up and becomes saturated with moisture. When the animal floats to the surface, the air exhaled by it with force, in contact with the cold outside, forms a column of condensed vapor - the so-called. fountain. Thus, whale fountains are not columns of water at all. In different species, they are not the same in shape and height; for example, in the southern right whale, the fountain at the top bifurcates. The exhaled air is pushed through the blowhole under such strong pressure that it produces a loud trumpet sound that can be heard from a great distance in calm weather. The blowhole is equipped with valves that close tightly when the animal is immersed in water and open when it rises to the surface.

In one breath, the dolphin renews up to 90% of the air in the lungs
The lungs are very resilient and elastic; lung tissue is adapted to rapid contraction and expansion. This provides a very short respiratory act and allows you to renew the air in one breath by 80-90% (in humans, only 15%). In the lungs, cartilaginous rings are strongly developed even in small bronchi, and in dolphins and in bronchioles, which are locked by ring sphincter muscles. Cetaceans can stay under water for a long time and dive deep, economically consuming oxygen.

Grabbers and filterers

Cetaceans swallow prey whole, without chewing, usually only live. Their way of feeding is sharply different, and depending on this, the detachment is divided into two suborders: toothed whales (grabbers) and baleen whales (filterers). Dolphins belong to the suborder of toothed whales. They grab prey one by one, holding it with their teeth, or with the help of their tongue they suck in several fish at a time when they open their mouths.

Plank-eaters, benth-eaters and fish-eaters
Cetaceans require large accumulations of food, which also determine the size of their herds. In connection with the main food, different types of the detachment prefer certain zones of the ocean. Some (plankton-eaters - smooth whales) feed mainly in the open sea near the surface of the water on mass accumulations of small crustaceans. Others (benthoses - gray whales) love shallow waters, where they use bottom and bottom crustaceans; still others (fish-eaters - most dolphins) hunt for schooling fish both far and near the coast, and occasionally visit rivers. There are also permanent inhabitants of the rivers, feeding on freshwater fish and various invertebrates (river dolphins).

Whales swallow food whole
and absorb up to a ton of feed per day. The sperm whale has a very wide throat, so that it can freely swallow a person, but in baleen whales it is much narrower and only allows small fish to pass through. The sperm whale feeds mainly on squid and often feeds at depths greater than 1.5 km, where pressures exceed 100 kg/cm2. The killer whale is the only representative of the detachment that regularly eats not only fish and invertebrates, but also warm-blooded animals - birds, seals and whales. Cetaceans have a very long intestine and a complex multi-chambered stomach, consisting, for example, of 14 sections in beaked whales, and 4 in smooth whales.

live in families
Dolphins live in families that include descendants of several generations. Such families are probably the same groups that are observed in areas of food concentration. Groups unite in temporary, sometimes very numerous herds, disintegrating as accumulations of food dissipate. Sometimes (in pilot whales) families converge into resting groups of several dozen heads and lie on the surface, exposing their muzzles and dorsal fins from the water. At times, families of dolphins, led by a male leader, unite for joint action against large sharks and break up when the danger has passed.

Throat like a ladder

At Blainville's belttooth (Mesoplodon densirostris) the lower jaw is very high, but sharply lowered in front of the tooth, forming a protrusion for the articulation of the left jaw with the right. The jaw is like a ladder, there is only one tooth at the top and bottom of the belt tooth.

hardest bone
found in the upper jaw of a whale belttooth Mesoplodon densirostris. It withstands a pressure of 2.7 grams per cubic centimeter. This bone is also notable for its chemical composition - it has 13 percent more calcium per unit weight than any previously known bone. However, its very structure is such that it splits very well along the microchannels located inside the bone. Scientists at the University of York who discovered this bone suggest that it serves to reflect and propagate the whale's sonar signals.

The most "gluttonous" whale

- blue- can eat up to 8 tons of food per day.

In the stomach of a whale
in the stomach sperm whale Physeter macrocephalus 28,000 crustaceans were found. Also in the stomachs of these whales were found shoes, wire, buckets, plastic bags and sand.

Killer whales don't attack humans

Orca killer whales, which are not whales but dolphins, do not harm humans. The size of these marine mammals is impressive - they reach 13 m.

A short, curved dorsal fin is found only in female and juvenile killer whales. In adult males, the dorsal fin is high and straight.

Longest pregnancy of all whales

In killer whales - lasts from 15 to 16 months.

whale sperm

does not sink for two hours and can spread on the surface of the water in the vicinity of a mile from the male. The sperm of a blue whale is equal in weight to the weight of four elephants.

Dolphins

There are over 450 animal species that have been observed to form homosexual pairs, including grizzly bears, flamingos, salmon and penguins.

Breeding in two years

Most cetaceans breed after two years, but some dolphins mate before they have finished nursing their young and breed annually. Pregnancy in different species lasts from 10 to 16 months. During the rut, fights between males are observed, after which teeth marks remain on the body of toothed whales. Childbirth in the water, but the first sip - in the air. The female gives birth to a cub once every 2 years.

Dolphins give birth in the water
At the time of childbirth, the female raises her tail high above the water, the dolphin is born in the air and has time to breathe before it falls into the water. For the first few hours, the baby dolphin swims like a float in an upright position, slightly moving its front flippers: it has accumulated a sufficient supply of fat in the womb, and its density is less than that of water. There is always a mother and one or two more females nearby.

Two hundred liters of milk a day

Australian whale calf Eubalaena australis from the southern seas of Australia drinks up to 200 liters of milk per day.

In three samples of humpback whale milk, the following was found: fat 45-49%, protein 8.6-9.7%, sugar 0.35-1.03% and the rest water.

The daily portion of blue whale milk is 200-300 liters.

Lips replace rolled tongue when sucking

The only, well-developed cub is born very large - from 1/4 to 1/2 of the mother's body length. Occasionally, several embryos are found in one female. The fetus comes out tail first. The umbilical cord is torn at the very belly, where it is less strong. The cub feeds on very fatty (up to 54%; milk) for from four (small dolphins) to 13 months (sperm whales), and in captivity even up to two years (bottle dolphins). mother's nipple, and she sprinkles milk into his mouth. All this happens under water: the respiratory canal is separated from the esophagus, and the dolphin can swallow food underwater without fear of choking. Cubs consume milk in small portions, but very often: in dolphins after 15- 30 minutes From the first day, the suckling swims next to the female: it turns out that this allows him to save strength and swim passively, using the pressure of the hydrodynamic field around the parent, who, as it were, “tows” his cub. With age, this habit weakens and disappears.

newborn baby whale

Annually gray whales (Mysticeti) migrate to warm waters for breeding, where females give birth to offspring. The calf leaves its mother tail first, and the newborn takes its first breath of air on the surface of the water, otherwise it will drown. Whale milk is very fatty, so the whale quickly gains weight and grows, soon he learns to swim, search for food and communicate with other whales.

Injured humpback whale calves Megaptera novaeangliae pushed to the surface, which causes them to breathe.

newborns

Newborn sperm whale has a length of 3.5 to 4.5 m. The weight of a newborn whale Beluga whales- 80 kg, and its length is 1.5-1.6 m. The weight of the newborn blue whale- 2-3 tons., length - 6-8 m.

A newborn goes through the whole gamut of blue
Beluga whales breed from spring to autumn, but the culmination of mating and childbirth occurs in the middle or end of summer. The cub is born after 11-12 months of pregnancy. In sucklings, the color of the body is slate-blue, in young ones (who have completed milk nutrition and have reached puberty) gray and blue.

Overpopulation is regulated

A number of mammals (reindeer, arctic foxes, whales, bats, etc.) are characterized by regular seasonal migrations. Some species (squirrels, lemmings) in some years due to overpopulation as a result of intensive reproduction, lack of food, etc. masses are evicted outside the range and die.

Whales, seals, penguins and many fish species could disappear from Antarctic waters
Many fish species, as well as whales, seals and penguins, living in the Antarctic region may be on the verge of extinction due to the sharp decline in food in these waters now recorded. The number of krill, small crustaceans that live near the surface of the sea and serve as food for a huge number of its inhabitants, is decreasing.

The number of krill has fallen by 80 percent in the ice continent since 1976. The decline in krill has not yet been clearly explained. However, it can be associated with a noticeable decrease in the amount of coastal ice, in the zone of which small crustaceans feed and escape from enemies. Its melting, in turn, is explained by the authors of the report as a greenhouse effect, which has caused an increase in temperature in Antarctica by 2.5 degrees Celsius over the past 50 years.

When is physical maturity

Sexual maturity occurs at the age of 3 to 6 years, but the slow growth of the body still continues for a long time. When the skeleton is completely ossified and all the epiphyses (bone ends) of the spine fuse with the vertebral bodies, then physical maturity occurs.

life span of cetaceans
Whales live up to 50, and dolphins - up to 30 years. The age of whales is determined in several ways: they count the scars remaining from the reduction of the corpus luteum on the surface of the ovaries, or the layers in ear chitin-like plugs.

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

Ambergris
Ambergris is extracted from the intestines of sperm whales; this greyish substance is secreted there as a result of mucosal irritation caused by the horny jaws of swallowed squids. Pieces of ambergris weigh up to 13 kg, and the mass of its largest "nugget" is 122 kg. It contains sodium chloride, calcium phosphate, alkaloids, acids and the so-called amber; this substance is lighter than fresh and salt water, softens in the hands, melts at temperatures below 100 °, and evaporates with stronger heating. Once upon a time, ambergris was highly valued as a fixative for perfumes.

Perish in nylon nets

Many whales and dolphins die when caught in nylon fishing nets. They cannot get out of these networks.

Delkitiha gave birth to a baby delkitikha

In a Hawaiian water park, a female Kekaimalu, a cross between a killer whale and an Atlantic bottlenose dolphin, gave birth to a calf. A young baby delkit is a quarter of a killer whale and three quarters of a bottlenose dolphin. Its shiny skin is a uniform combination of light gray dolphin and black killer whale. The cub still feeds on its mother's milk, but sometimes it quickly snatches the frozen capelin from the trainers' hands, and then plays with the fish. Compared to purebred baby dolphins, she is a giantess - already twice the size of a one-year-old bottlenose dolphin.

Whale maturity and lifespan

Sexual maturity of humpback whales occurs at 5-6 years, when 10-11 layers are formed in the ear plugs, and the body length of females reaches an average of 12 m and males 11.7 m. Full growth occurs at 15-17 years, at 30-35 layers in ear plugs and a length of females 14.8 m and males 13.6 m. The oldest males were 48 years old and the oldest females 38 years old.

Humans set the record for longevity among mammals. Another long-lived whale can be considered Balaenoptera physalis, which lives up to 90-100 years.

Indonesian fishermen claim

Indonesian fishermen claim that just before the 2004 tsunami, a pod of dolphins pushed their boat into deeper, safer waters.

Recent genetic studies of dolphins suggest that the ancestors of animals are ungulates. These are their closest relatives. The answer to the question about how many chromosomes do dolphins have, suggests a hypothesis about the primary habitat of these mammals on land.

How many chromosomes do dolphins have

Chromosomes are the special structure that makes up DNA. It is located in the nucleus of the cell of the body. The task of the chromosome is to store information about the structure of the body, its individual characteristics and gender. The dolphin has 44 chromosomes. Since they are located in cells in double quantity, there are 22 pairs in total. A certain set of chromosomes establishes the karyotype of any representative of the animal or plant world.

The number of chromosomes in other inhabitants of the sea:

  1. Penguin - 46.
  2. Blue whale - 44.
  3. Sea urchin - 42.
  4. Shark - 36.
  5. Seal - 34.

Dolphins belong to the species of cetaceans, subspecies - toothed whales (dolphins, sperm whales, killer whales). In total, there are about 50 species of dolphins. They mostly live in sea water, but there are a few varieties that live in large rivers. Dolphins, like terrestrial animals, warm-blooded, viviparous, feed their young with their milk. They breathe with lungs, for this they emerge from the water several times during the day. A dolphin is completely different from a shark. The sea predator belongs to the class of fish, as it has gills, and its offspring do not feed on milk. Sharks don't have milk.

genetic research

Dolphins communicate with us

The existing theory about the origin of humans from monkeys has become less convincing after recent studies of dolphin chromosomes. As it turned out, humans and dolphins have a striking similarity in chromosome structures. Among other organisms living on earth, the dolphin was closest to the artiodactyls and the hippopotamus. Many similarities have been found with elephants. Human, dolphin and elephant are distinguished by the proportional volume of the brain relative to the body. The special structure of the nervous system determines a significant number of synapses (nerve connections) and cerebral convolutions. These properties allow dolphins to learn quickly.

Dolphins have higher intelligence than monkeys. Marine inhabitants recognize themselves in the mirror, understand the intonation of human speech, know how to imitate and strictly follow the rules that have developed in the flock. Cetaceans communicate using low-frequency sounds. Sea water contains magnesium sulfate, which absorbs high frequency noise. Therefore, the inhabitants of the sea have learned to use sounds that can propagate in the water over long distances.

The human genes responsible for sleep are simply mutated in dolphins. Therefore, these mammals sleep in a special way. In the process of research, scientists have discovered DNA that is responsible for the wakefulness of one half of the brain while the other is sleeping. This happened in the process of mutation. Scientists have concluded that after humans, dolphins have the highest intelligence on the planet.


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Order: Cetacea Brisson, 1762 = Cetaceans

The organs of hearing are greatly modified. The auricle is reduced. The external auditory meatus opens behind the eye with a small opening. An interesting opinion is that the rudimentary auditory canal can serve as an independent sensory organ that perceives changes in pressure. The eardrum curves outward (baleen whales) or inward (toothed whales). From the outside, the eardrum of baleen whales is covered with a kind of ear plug, consisting of keratinized epithelium and earwax. Cetaceans are capable of capturing a wide range of sound waves from 150 to 120-140 thousand Hz (Slijper, 1962), i.e., even ultrasonic vibrations. The high degree of development of the auditory parts of the brain of toothed whales indicates a special acuteness of their hearing, almost unique among mammals; baleen whales have poorer hearing compared to land mammals. Cetaceans are capable of echolocation, as are bats. Since cetaceans do not have vocal cords, they cannot make sounds in the usual way for mammals. It is possible that sounds are produced as a result of the vibration of the lower part of the septum between the nasal sacs or the vibration of the fold of the external valve as a result of the passage of air from the dorsal nasal sacs. Dolphins are capable of emitting series of short sound pulses, the duration of which is 1 ms, and the repetition rate varies from 1-2 to several hundred hertz.

The body temperature of cetaceans is similar to that of terrestrial mammals and ranges from 35 to 40°C (the upper limit was noted in injured whales or dolphins caught after pursuit). Preservation of high body temperature in water, which conducts heat many times better than air, is carried out by a thick layer of subcutaneous fatty tissue in the skin.

In female baleen whales, the genital and anal openings are separated from each other by a considerable space, while in toothed whales they are located in a single depression and are surrounded by a common sphincter. Males are constantly or very long during the year capable of fertilization. It has been suggested that ovulation in cetaceans is provoked by sexual intercourse. In females, at the beginning of pregnancy, two or three embryos may be in the uterus, of which only one soon remains. Diffuse placenta.

Childbirth takes place under water. The cub is born fully developed, capable of independent movement. The proportions of its body are very similar to the proportions of the body of adult whales, and the dimensions reach 1/2-1/4 of the body length of the mother. Females of some cetaceans can be fertilized shortly after giving birth during the lactation period. Feeding of the cubs is done under water, the duration of each meal is a few seconds. Milk is sprayed into the mouth of the baby by contraction of special muscles of the female. The mammary glands of the female are located on the sides of the genital opening. Two nipples (one on each side) lie in slit-like folds and protrude only during lactation. Female whales produce different amounts of milk per day: from 200-1200 g in dolphins to 90-150 liters in fin whales and 200 liters in blue whales (Sleptsov, 1955). The milk is thick and usually cream-colored. It is characteristic that its surface tension is 30 times greater than that of water, which is especially important, since the stream of milk does not blur in water. The nutritional content of whale milk is very high.

The growth of cubs during feeding them with milk occurs quickly. For example, a blue whale calf grows from 7 to 16 m in 7 months of life, i.e., the average daily increase in length is 4.5 cm.

Sexual dimorphism is manifested mainly in the different body lengths of males and females. Female baleen whales are larger than males, while most toothed whales, on the contrary, are smaller. The diploid number of chromosomes in tweeds of toothed whales and 4 species of baleen whales (sei whale, minke whale, fin whale and gray whale) is 44, and in sperm whales - 42.

Distributed in all oceans and in most seas of the globe. Factors that determine the distribution of cetaceans are food availability and water temperature. Some species are widespread and are found both in warm and cold seas (some species from the dolphin family), others have a smaller range (gray whales live in subtropical, temperate and cold waters of the northern half of the Pacific Ocean and in the Chukchi Sea), the range of others even more limited (narwhal does not leave the waters of the Arctic), and finally, the range of river, lake and estuarine forms is quite insignificant.

Most species are herd animals; They live in groups from a few heads to hundreds and thousands of individuals. They are found both near the coasts and in the open sea. Representatives of some species are able to climb up large rivers that flow into the sea, and some species live permanently in rivers. Most whales have a specialized diet, and among them there are planktophages, teutophages, ichthyophages and sacrophages. They feed on mass or piece prey. Among cetaceans, there are fast swimmers (killer whales, many dolphins) and relatively slow moving ones (gray whales). Most whales are constantly kept in surface waters. Some, such as sperm whales, can dive to considerable depths. The number of different species of cetaceans is not the same. Many of them are very numerous and can be found in herds of thousands (dolphin-dolphin), others, on the contrary, are very rare and meetings with them have been noted only a few times (some representatives of the genus of belt-toothed, pygmy sperm whale).

Excessive fishing has a detrimental effect on the number of whales, significantly reducing it, and in some cases may threaten the complete destruction of these animals. Thus, the currently negligible number of bowhead whales is a consequence of the predatory killing of these once numerous animals.

Most species are characterized by periodic migrations. For some species, the length of migration routes is relatively small (the Azov-Black Sea porpoise - from the Sea of ​​\u200b\u200bAzov to the Black Sea and back); others are huge (some large whales - from tropical waters to high latitudes).

Cetaceans are predominantly monogamous. Mating periods and puppies are usually extended in time. They give birth to one, rarely two cubs. Strongly developed maternal instinct.

Enemies, except for a man and a killer whale, practically do not have. The remains of dolphins have been found in the stomachs of tiger and Greenland sharks.

The practical significance in the recent past was quite great. Some of the cetaceans are still harvested annually in large quantities (sperm whales), while others are hunted only occasionally. Almost all whale organs are used to produce valuable food and technical products. Fishing for cetaceans can only be carried out with strict observance of the measures necessary to maintain their numbers. At present, in order to preserve cetaceans, it is advisable to stop their fishing for a number of years.