A message about the diversity of animal whales. Cetaceans: general characteristics of the order of aquatic mammals

Cetaceans - whales, dolphins and porpoises - a detachment of exclusively aquatic mammals that look like fish, but differ from them in the presence of warm-bloodedness, pulmonary respiration, gestation in the uterus and feeding with milk. In these and some other features, they are similar to other mammals, and the general plan of their structure also indicates that they belong to this class animals.

The resistance of water is 800 times greater than in air, so the streamlined torpedo-shaped body shape was formed in cetaceans as an adaptation to an aquatic lifestyle. The coat, hind limbs and ears are a hindrance when moving in the aquatic environment, therefore they are absent in cetaceans. The forelimbs have turned into pectoral fins - these are elevators, turns and braking; they also provide the movement of the body back. Most species of cetaceans have a dorsal fin, which gives stability to the body in the water. A thick subcutaneous layer of fat protects the body from cooling and is used as an energy reserve during seasonal hunger strikes of cetaceans, so it varies greatly with the seasons of the year. The loss of hind limbs, sacral spine and pelvis not only increases the freedom of movement of the caudal peduncle, but also allows cetaceans to give birth to very large and developed young. The skull of whales is adapted so that breathing takes place when the nostrils are exposed from the water without bending the neck (the nostrils are shifted to the top of the head). The blowhole - one or two external nasal openings - is located at the top of the head and opens only at the moment of a short respiratory act of exhalation - inhalation, produced immediately after emerging. In cool weather, when exhaling, condensed steam flies up, forming the so-called fountains, by which whalers distinguish the type of whale. Sometimes atomized sprays of water also take off with this steam. The rest of the time, while the respiratory pause lasts and the animal dives, the nostrils are tightly closed with valves that do not let water into the respiratory tract. Cetaceans can stay under water for a long time (sperm whales and bottlenose up to 1.5 hours) with the same air supply: a large lung capacity and a rich content of muscle hemoglobin allow them to carry away an increased amount of oxygen from the surface, which is consumed very economically. During diving, the pulse slows down by more than half and the blood flow is redistributed so that oxygen is supplied primarily to the brain and heart muscle. Tissues less sensitive to oxygen starvation (especially the muscles of the body) are transferred to "starvation rations". The reduced sensitivity of the respiratory center to the accumulation of carbon dioxide in the blood allows cetaceans to lengthen the respiratory pause and use it for feeding.

Cetaceans are very voracious. Whales absorb up to a ton of food per day! 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.

Cetacean births occur underwater. Kittens already from the first minutes of life are oriented in the aquatic environment.

All cetaceans hear very well underwater, and toothed whales, like bats, have the ability to echolocate, which largely replaces the eyes, which are limited in the water. Cetaceans are capable of capturing a wide range of sound waves from 150 to 120-140 thousand Hz, that is, even ultrasonic vibrations. Due to the fact that cetaceans do not have vocal cords, they cannot make sounds in the usual way for mammals. It is possible that the sounds are produced as a result of the vibration of the lower part of the septum between the 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.

Whales live up to 50, and small ones - up to 30 years.

The distribution of most species of cetaceans is very wide, which is facilitated by the absence of pronounced barriers in the ocean. Cetaceans live in local herds, possibly families, 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), heat-loving species (Bride's minke), tropical and subtropical (many dolphins, pygmy sperm whales) and species with a wide range, including cosmopolitans (almost all minke whales, sperm whales, orcas, etc.).

As a result of adaptation to seasonal feeding and breeding conditions, whales have formed several biological groups. Some species began to make strictly regular migrations within the Northern or Southern Hemisphere: for the winter (almost all baleen whales, part of beak-winged whales and sperm whales) swim to low latitudes for childbirth, and for summer - to moderate and high latitudes for fattening. (There are 10-20 times more planktonic organisms in the feeding fields in the Arctic and Antarctic than in the tropics.) Other species (killer whales, pilot whales, partly sei whales, narwhals, etc.) began to move, although over considerable distances, but less regularly and with seasonal irregularities. The third group (bottle dolphins, river dolphins, gray dolphins, etc.) switched to a relatively settled way of life: their migrations take place within a small water area.

Detachment cetaceans It is divided into two suborders: toothed whales and baleen whales. 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.

Humans have hunted whales since antiquity, and whaling has existed since before the 10th century. In addition to meat, whale oil (blubber), which is used to make soap and cosmetic creams, is of great value. Vitamin A is extracted from the liver of whales, ambergris is extracted from the intestines, which gives firmness to spirits. As a result of uncontrolled mining, the whale population has been greatly reduced and some of their species are on the verge of extinction. To protect cetaceans from extermination, 18 countries have entered into an international agreement regulating the size of fisheries. The agreement prohibits the production of smooth, gray, blue and humpback whales. Suckers, lactating queens and immature individuals of all species of whales are not subject to slaughter. The total production should not exceed the quota (cut-out rate) set for each year. In the oceans, restricted areas for whaling have been set aside; the duration of the whaling season cannot exceed the established time limits.

Order Pinnipedia (Pinnipedia)

Large mammals adapted to long stays in water (in the seas and some large lakes) and move poorly on land. The order includes 31 species. These include walruses, eared seals (seals, etc.) and real seals. Pinnipeds originated from land predators, with which they are still sometimes combined into one order. In connection with adaptation to life in water, the body shape of pinnipeds is streamlined, the head is round, devoid of auricles or with their rudiments, the coat is short, hard (in seals - with a soft undercoat), in adult walruses it is completely rudimentary. Limbs have turned into flippers, fingers are connected by a swimming membrane. In walruses and eared seals, the hind limbs can still be bent, while in seals they are constantly turned back and located along the tail (short in pinnipeds). The subcutaneous fat layer is very thick, protects the animal from exposure to low temperatures (retains heat) and facilitates body weight. Some species have air sacs branching off from the trachea or even from the esophagus; they make it possible to have a supply of air when diving and reduce body weight. The forebrain is well developed. The eyes are large, with a spherical lens, which makes it possible to see in the water. The dental system, due to the fact that it is impossible to chew in water, has become simpler: the teeth are homogeneous, their number has increased, they serve only to capture prey. In walruses, the upper fangs have turned into powerful tusks, with the help of which these animals dig mollusks from the bottom. Pinnipeds feed on fish and various invertebrates (mollusks, etc.). Reproduction takes place on land. Pinnipeds are mostly herd animals.

Pinnipeds are harvested for their meat, fat, hides and fur. Very valuable fur is given by seals. Fishing for pinnipeds is limited everywhere, but their numbers are declining. A number of species are listed in the Red Books.

Pinnipeds - a group of mammals, which was previously separated into a separate detachment, uniting seals and walruses.

These are medium-sized or large (even very large - the elephant seal weighs 4-5 tons) animals adapted to life in the water. They get food only there; but breed exclusively on land. In this, pinnipeds differ from whales and sirens and therefore are rightly considered semi-aquatic animals. In total, there are 35 species of pinnipeds in the world fauna, in Russia - no more than 15.

By evolutionary standards, these sea animals appeared quite recently, some 25-30 million years ago. Their ancestors were terrestrial predators, and it has been established for certain that different representatives of the order of pinnipeds descended from different branches of predators. The so-called eared seals - sea lions, seals, walruses - have common roots with bears, and real seals - such as seals - with mustelids. Because of this heterogeneity, pinnipeds are often deprived of the “right” to be considered an independent detachment, they are included in the predatory ones.

The general appearance of pinnipeds is quite "marine". They have an elongated cigar-shaped streamlined body, almost no tail, legs turned into flexible flippers, fingers entirely enclosed in a swimming membrane. The two branches of pinnipeds differ greatly in the device of flippers. In the "bearish" line, the front flippers are very large and wide, the hind flippers have retained the ability to bend forward, the animals can move on the earth's firmament on their feet, but swim mainly with the help of the front flippers. In the "marten" line, on the contrary, the hind limbs are more developed, but they can no longer bend forward: these seals move on land only on their belly like a shrew caterpillar, they make similar wave-like movements with their whole body when they swim. Unlike carnivores, the dental system of pinnipeds is little differentiated: only large fangs stand out, and the teeth located behind them are small and rarely sit. Their purpose is not to tear the prey, but only to grab and prevent it from escaping.

Representatives of the order are inhabitants of predominantly cold waters off the mainland coasts; only a few are found in tropical waters. Two types of seals settled in inland waters - in the Caspian Sea and in Baikal. These animals almost always live in large clusters, gathering on coastal haulouts or on ice floes in hundreds or even thousands of individuals. They feed on small food, which they swallow whole: mainly fish, some eat crustaceans and mollusks. The cubs will be born fully developed - sighted, can actively move on land, and shortly after birth in the water.

Many pinnipeds were an important object of the fur trade. Due to predatory prey, the number of such animals as the fur seal, walrus, and some seals has sharply decreased; they are protected by law.

Aquatic mammals with a spindle-shaped body, five-fingered fore and hind limbs turned into fins (fins), whose fingers, equipped with claws, are connected by a thick swimming membrane, hind limbs directed horizontally backward, a complete dental system (of incisors, canines and molars), one or two pairs of nipples on the belly, a bicornuate uterus and an annular afterbirth.

In some pinnipeds, the toes are completely immobile, and their boundaries are indistinguishable upon external examination. Some pinnipeds, when on land, step over with their hind flippers, while most species simply drag them. The relatively small head separates quite clearly from the neck, but the neck itself, short and thick, passes directly into a rounded body, tapering at the back. The tail is a small process. The muzzle of pinnipeds is short, rounded in front, the mouth is deeply cut, on the upper lip there are mustaches made of elastic bristles. The nostrils are slit-like, located obliquely, when they are in the water they are closed with valves. The eyes are large, with a nictitating membrane; the ears in most species do not have an external shell. The skin is thick and dense. In some, she is almost naked, while in others she is covered with long, coarse hair. The predominant coat color is yellowish-gray or yellow with a reddish tint. The fat layer of the skin is well developed, reliably protecting the body from heat loss.

They feed on fish, crustaceans, mollusks.

Pinnipeds are common in all seas of the world, enter rivers and large lakes and are found even in the inland lakes of Asia, remaining there after the retreat of the seas and oceans.

60. equids, specific traits buildings. Representatives. The evolution of horses, the significance of research by V. O. Kovalevsky

Odd-toed ungulates (Perissodactyla).

Odd-toed ungulates, or odd-toed(lat. Perissodactyla) - a detachment of large and very large land mammals. Unlike artiodactyls ( Artiodactyla) they are characterized by an odd number of fingers forming hooves. The order contains three modern families - horses ( Equidae), rhinos ( Rhinocerotidae) and tapir ( Tapiridae), which together comprise 17 species. The relationship of these outwardly very different families was first established by the zoologist Richard Owen in the 19th century, who also coined the name equids (Eng. odd-toed ungulates).

Until relatively recently, these ungulates were widespread and numerous. At present, only tapirs, rhinos and horses remain. The number of fingers is different: in tapirs, the front legs are four-toed, the hind legs are three-toed, in rhinoceros all legs are three-toed, in horses they are one-toed. Characteristic of all equids is the strong development of the third finger, through which the axis of the limb passes, in horses it remains the only one. There are no keys. All equids are large animals.

The tapir family (Tapiridae) is the most primitive of modern equids. Like the extinct ancient members of the order, they have polydactyl limbs, live in forests and feed on soft vegetation. Tapirs were once widespread in different parts of the globe, but then were replaced by more advanced equids and are now preserved in the marshy forest thickets of Central and South America and Southeast Asia. Such a "broken" distribution is characteristic of many endangered forms.

The rhinoceros family (Rhinocerotidae) are huge, strong animals (up to 5 m long and weighing more than 2 tons) with very thick skin devoid of hair. On the nasal and frontal bones they have one or two horns. These odd-toed ungulates live in South Asia and Africa. They were widespread during most of the Tertiary, and some of them lived as far back as the Quaternary. Now included in the Red Book.

The horse family (Equidae) is the most progressive group of equids adapted to life in open spaces - in the steppes and semi-deserts. Animals are strong, run fast, their senses (especially hearing and smell) are well developed. Modern horses belong to the same genus - the horse (Equus), which includes four species (other authors distinguish them into special subgenera). In a special subgenus, for example, zebras are distinguished. These animals with a characteristic striped pattern live on open places different parts of Africa. Some zoologists attribute all zebras to one species, which is divided into several subspecies, while others distinguish three independent species. Wild donkeys (Equus asinus) have survived in northern Ethiopia, Somalia and Eritrea. From them came domestic donkeys. In the semi-desert regions of Asia (Turkmenistan, Iran, Afghanistan, Mongolia, China, Tibet, Western India, etc.), kulans (Equus hemionus) live. These animals are often called half-donkeys, but according to other authors, kulans should be considered primitive horses. Przewalski's wild horses (Equus przewalskii), named after the great Russian traveler N.M. Przewalski, who discovered it, have survived in the wild, perhaps only in Central Asia, although until recently they were common in the steppes of Europe and North Asia. In Europe, the last wild horses close to the Przewalski's horse - tarpans (Equus gmelini) - were exterminated in the middle of the last century. From whom exactly domestic horses originated is not exactly established, it is possible that from several wild species close to each other.

Whales are very peculiar mammals, which, due to their constant life in the water, are more like fish. This group of animals has a characteristic appearance and at the same time achieved considerable diversity. Whales make up a separate order of cetaceans, but this term is collective. Usually, this word means large species, small cetaceans have other names (dolphins, porpoises).

Humpback whale, or humpback whale (Megaptera novaeangliae).

The most striking distinguishing feature of these animals is their size. Indeed, all types of whales are simply giants of the animal world. Even the smallest species (dwarf sperm whales, for example) reach a length of 2-3 m and a weight of 400 kg, and most species are 5-12 m long and weigh several tons. The largest species - the blue whale - reaches a length of 33 m and weighs 150 tons! It is several times larger than even the largest dinosaurs. The blue whale is the largest of all living creatures that have ever inhabited our planet!

All types of whales are characterized by an elongated streamlined body, a very short, inactive neck and a large head. Head size can vary greatly between species: in small whales, it is 1/5 of the body length, in large baleen whales, its size can reach 1/4, and in sperm whales, the head is 1/3 of the body. According to the structure of the teeth, two suborders of whales are distinguished - baleen and toothed. Baleen whales have no teeth at all, they are replaced by giant horny plates that hang down in their mouths like a fringe. They are called whalebone.

Whalebone in the whale's mouth.

Toothed whales have teeth, their shape and size varies from species to species. The structure of the jaws can also be different: in baleen whales, the lower jaw is much larger than the upper and similar to a bucket, in toothed whales, on the contrary, the upper jaw is larger or equal in size to the lower. Such differences are associated with the nature of the diet of these animals.

On the head of a humpback whale, the difference in the size of the upper and lower jaws is clearly visible.

The brain size of whales is relatively large, but this is primarily due to the development of the parts of the brain responsible for hearing. Whales, like dolphins, have perfect echolocation abilities, they emit sounds of various frequencies and, by their reflection (echo), they orient themselves in space, find food and communicate with each other. Just like dolphins, whales are subject to an incomprehensible pathology - they can periodically be washed ashore. Animals do this unconsciously (the ability of whales to commit suicide is nothing more than a stupid prejudice), but with such persistence that scientists are still scratching their heads over the reason for such strange behavior. Animals that have washed ashore are not always old or sick, moreover, sometimes they can be returned to the sea through the efforts of rescuers. Most likely, the root cause of such death is disturbances in the operation of the echo sounder caused by numerous radio sources (all modern navigation uses powerful sources and repeaters of radio waves). Such electromagnetic "noise" in the ocean confuses the giants and they approach the shores, moreover, accustomed to trusting their feelings, the whales stubbornly strive in the "right" direction until they run aground. Other sense organs in whales are poorly developed: the sense of smell is in its infancy, and vision is also rather weak.

On the top of the head is a breathing hole - blowhole. In more primitive baleen whales, it consists of two holes (“nostrils”), in toothed whales there is one hole. Interestingly, during exhalation, moist air from the lungs creates a kind of fountain, and its shape depends on the type of whale.

A blowhole with two nostrils on the head of a gray whale (Eschrichtius robustus).

The limbs of whales are very unusual. The front ones have turned into flattened fins, and their size can vary greatly in different species. For example, the fins of the belt-teeth and sperm whales are small, and they reach the greatest development in the humpback whale.

The long fins of the humpback whale under water resemble wings.

But the whales have no hind limbs at all, in their place in the lumbar spine there are only two small bones, to which the muscles of ... the genital organs are attached. The powerful double tail creates the driving force in the body of the whale, but these are not modified hind legs, as some believe.

The powerful tail is used by whales for movement and protection.

The coloration of whales is varied, but discreet. More often their body has a dark upper side and a lighter lower side, in some species (Bride's minke whale) there may be clearly visible stripes on the underside of the head. Species such as blue, gray whales, sperm whales have a uniform color of gray or brown.

Beluga whale (Delphinapterus leucas) got its name from the rare White color skin.

Whales are distributed throughout all the oceans (and some seas) of the globe. They are found only in deep waters, as a rule they do not enter bays, estuaries and similar shallow places. Usually, whales move freely in the ocean, but their movement is not chaotic. Each species of whale has a favorite breeding ground that they visit during a particular season. The rest of the time, whales fatten up, but they do it in areas remote from breeding grounds. Thus, whales make migrations with a cycle of 1 year. During feeding, the whales swim at a speed of 10-20 km/h, but in case of danger they switch to a cruising speed of 50 km/h. Adult males and non-breeding females keep alone, females with cubs, as well as all animals during the breeding season form herds of 5-15 individuals. A peaceful situation reigns inside the herd: whales do not have an internal hierarchy, they do not show aggression towards each other, in case of danger, all members of the herd try to defend themselves by joint efforts, there are even cases of mutual assistance to wounded brethren. In general, whales, with their huge size and sluggishness, give the impression of stupid and uninteresting animals. But this is a misconception! These peculiar animals are endowed with a developed intellect and are not inferior to dolphins in intelligence. For example, there are cases when whales showed interest in underwater photographers filming them - animals approached people and even tried to play with them in their own way, pushing them to the surface. Another example: whalers tracked down a female whale with a calf and killed the latter. The carcass of the whale was transported to the place of butchering in tow. All this time, the female swam nearby and tried to remove the corpse of the cub from the rope. Captive whales in captivity quickly get used to people and are able to perform tricks (to the best of their physical abilities). Like all highly developed animals, whales love to play, while they jump high out of the water and beat their tails loudly.

Minke whale (Balaenoptera acutorostrata).

Whales feed on various marine animals, and there is a narrow specialization in the nutrition of different species. Baleen whales eat only plankton - the smallest marine crustaceans. They get it by filtering large volumes of water. To do this, the whale opens its mouth and draws water into its mouth ...

Humpback whales act like a scoop with their open mouth.

then, with his tongue, he pushes the water out of his mouth like a piston - the water flows freely through the whalebone, and the crustaceans remain.

The whale strains water with plankton.

Toothed whales feed on fish, which are also caught not individually, but in whole flocks. Sperm whales specialize in catching deep-sea fish and shellfish (mainly squid). Many whales make long dives for hunting, they can stay under water for up to 1.5 hours. The record holders for the depth of diving are sperm whales, which were met at a depth of 1 km!

Whales are very infertile animals. Females reach puberty by 7-15 years, males - only by 15-25. Moreover, each individual participates in reproduction no more than once every 2 years. In the mating ritual of whales, not only is there no aggression, but in general any kind of struggle. Male whales win the attention of females with songs! The voice of whales is surprisingly thin for animals of this size. Each species of whale has its own set of sounds, but even individuals of the same species differ in tone of voice. The song of the whale resembles a melodic moan and sounds very loud. According to divers, when the whale sings, the water column vibrates around. Female whales can mate with several males, since there is no fight between the stronger sex, selection occurs in a very unusual way. It turns out that the gonads of whales are huge (in a sperm whale, for example, up to 10-20% of body weight) and are capable of producing a large number of sperm. Thus, among several males mated with one female, the one whose hormonal status is higher wins. Pregnancy in various species lasts 11-18 months. The female gives birth to only one cub, but large and developed. For example, the weight of a newborn blue whale is 2-3 tons. The calf is born tail first and with the help of the mother rises to the surface for the first breath. The mother often feeds the cub with very fatty milk, thanks to which it grows rapidly. The lactation period in whales is relatively short - 5-7 months. During this time, the cub manages to grow 2 times, then its growth slows down sharply. For another 1.5-2 years, the cub accompanies its mother, using her protection. In small and medium-sized whales, young are kept in herds until they reach sexual maturity, and sometimes even later. Whales live 50-70 years.

Blue whale calf (Balaenoptera musculus).

It would seem that nothing can threaten such gigantic animals in this world. In reality, whales are very vulnerable to various dangers. In the ocean, whales have no enemies, except for ... their own brethren. Killer whales (giant predatory dolphins often referred to as whales) attack other cetacean species. Killer whales live in groups and act collectively, so even adult whales can hardly resist their coordinated attack, and the cubs are completely defenseless. When attacked, the whales try to escape by “flight”, swimming away from the herd of killer whales at high speed. If it was not possible to break away from the pursuit, the whale tries to fight off the attackers with strong blows of the tail, the mother swims under the cub from below, trying to cover it with her body.

But even in the absence of predators, whales have enough problems. Sometimes these animals experience… hunger. Mass fishing, global warming, changing sea currents undermine the food base of whales and animals can drift for several weeks in "barren" waters. Researchers have seen extremely emaciated animals. In the Arctic Ocean, whales often get caught in ice traps. Since whales breathe air, they are forced to surface regularly to replenish their supplies. If there are no suitable polynyas around, the whales break through the thickness of the ice with their heads, but they do not always succeed. With a large thickness of ice (or a small width of the polynya), entire herds of whales suffocate under the ice.

Minke whale in the Antarctic ice.

To top it all off, whales are actively hunted by people. Despite their impressive size (or rather, thanks to them), whales are attractive prey for fishing. There are no useless parts in the carcass of a whale, everything is used: fat (blubber), meat, whalebone, teeth, skin. Sperm whales are suppliers of very exotic products - spermaceti and ambergris. Spermaceti, despite the name, is not whale sperm at all, but a fat-like substance from the brain. Ambergris is found in the intestines, it has a pleasant smell, for which it got its name. Both substances are very valuable raw materials in the cosmetic industry and are extremely highly valued on the world market.

As a result of the impact adverse factors the number of almost all species of whales has been greatly reduced, many species are on the verge of extinction. In this regard, the World Convention on the Prohibition of Whaling was adopted (especially since whaling products have lost their relevance in our time). The only country that has not signed the convention is Japan. Japanese whalers still carry out mass hunting of all whales indiscriminately, justifying themselves by the fact that whale meat is ... a traditional component of Japanese cuisine. On the other hand, tourism in whale breeding areas has gained wide popularity. Nature lovers visit such places on small boats, for the opportunity to watch whales live and hear their songs, queues line up for tour operators. Attempts to keep whales in captivity run into many obstacles: large species of whales cannot be kept because of their size, baleen whales cannot be fed with plankton, it is very difficult to catch an adult whale without killing it. Repeated attempts to catch the cubs led to the death of the babies at the stage of transportation. Only the smallest species of whales (beluga whales, pilot whales) take root in aquariums, but they do not breed there. Perhaps, the only way conservation of these unique animals is the widespread ban on their production and the comprehensive protection of water resources.

The carcass of a beached blue whale is cut up for further scientific research.

About whales.

Since ancient times, in the mythology of various countries and peoples, there have been references to terrible monsters from the depths of the sea that eat people and let ships sink to the bottom. In myths Ancient Greece these monsters are called "kitos" ("sea monster"). In fact, this word came from modern name"whale".

Whales are the largest creatures on the globe. These are huge mammals that have chosen the waters of the oceans for their residence.

Scientists distinguish three main orders of whales that lived and live on Earth today: baleen whales (or Mysticeti), toothed whales (Odontoceti), ancient ones (Archaeoceti) - a long-extinct group. All three of these orders include about 130 living and 40 extinct species.

Appearance, dimensions, body structure.

All cetaceans are impressive in size, but depending on the species, the body of a whale can reach a length of 2 to 25 m. The largest are blue (blue) whales, and the smallest are white-bellied dolphins.

Cetaceans are perfectly adapted to life in the aquatic environment. Despite the fact that outwardly they resemble fish, the structure and characteristics of the body in these two classes are very different. Whales are warm-blooded animals. Their body is usually teardrop-shaped or torpedo-shaped. The streamlined body is covered with fine hairs that do no harm, but no benefit either. The body ends with two powerful flat fins. And although they do not have a bone base, they consist of very dense cartilage. Thus, the tail performs the main function of moving the animal forward.

Pectoral fins are modified limbs of land mammals. When the whale moves, they act as a rudder, a directional regulator. The whale's body does not have any glands other than the mammary glands.

Thanks to the streamlined body, whales are able to overcome the resistance of water. This is also facilitated by the absence of hairline and auricles. In addition, the survival of whales in cold currents is helped by a thick layer of fat, which protects the animal from hypothermia.

Habitat and lifestyle.

Whales are ubiquitous, in all oceans and in almost all seas. Many species choose polar arctic waters, some can be found in warm tropical and subtropical latitudes.

Most of the whales are gregarious individuals. Animals are kept in groups ranging from ten to several hundred, and even thousands of individuals.

Whales also differ in gastronomic preferences - most of them feed on plankton or small fish. The most predatory species of whale - killer whale (although it is correct to call it killer whale) - eats even small land animals.

Many whales migrate annually in the currents in search of a new habitat with an abundance of food. Some, mostly small species, can even move in rivers.

Reproduction and feeding of babies.

For the most part, whales are monogamous creatures. Although males have the ability to fertilize all year round, most of the species bring offspring every 1.5-2 years. The duration of pregnancy (depending on the species) ranges from 7 months to one and a half years. Cubs are born right under water, and already quite developed, capable of movement.

The baby consumes mother's milk often and in small portions. Within a few seconds, the female injects milk into the baby's mouth. On average, a female can produce up to 1 liter of milk per day, which is quite enough for the full development of the baby. Since whale milk has a very high fat content, babies grow by leaps and bounds.

At the age of about 5 years, the whale reaches sexual maturity, but the process of growth and development of the body stops only after 10-12 years of life. Average duration The life of cetaceans ranges from 30 years (for small species) to 50 years for giants.

To date, many species of whales are listed as endangered, and hunting for them is prohibited in many countries by an international moratorium.

Whales are one of the most amazing mammals inhabiting the water expanses of our planet. These animals are the largest of all today known to mankind. Moreover, the ocean is still not fully explored, which is why scientists periodically discover new species of toothed whales, usually small, but still. today has led to the fact that the species of whales are constantly decreasing, as well as their population, which is very sad.

Classification

All whales are divided into two large groups, the so-called suborders. Although it is worth noting that scientists distinguish three suborders. One of them is ancient whales. All representatives of this group died out long ago, and there is no special sense in describing them. We will talk about animals that still swim in the oceans and seas, although there is a threat of their extinction.

One of these suborders is baleen whales. In addition, they are often called "real whales." The second suborder is toothed whales. Smaller representatives, which include dolphins and porpoises, but more on that later. I would like to point out that different types whales are exterminated. In particular, this applies to those who have the greatest value in the fishery. This is a blue whale, fin whale, humpback whale, etc.

Types of whales: list, brief description

We will start with both the largest and oldest. This includes a wide variety of whale species that are worthy of your attention. It is easy to guess that you can recognize such an animal by its mustache in its mouth. By the way, whalebone is also valued, so these animals often become prey for poachers. The largest representative of this suborder is the blue whale. The largest recorded individual reaches a length of about 30 meters and weighs 150 tons. Moreover, these are completely peaceful animals, the diet of which for the most part is plankton and mollusks.

The bowhead whale is a prominent representative of the baleen whales. The length of this giant sometimes reaches 20 meters, the body of the animal is black, without stripes. It is noteworthy that the head is approximately 30% of the total length of the whale. It lives exclusively in the Arctic seas. Today it is an almost extinct species, which is extremely rare. The reason for this was whaling.

Pygmy and right whales

The southern right whale is somewhat similar to the bowhead whale in both appearance and size. Therefore, an inexperienced person can confuse them. Although it is easy to guess that the habitat of animals is very different. Southern right whales cannot be found in the Arctic seas, just as bowhead whales cannot be seen in the temperate zone of the Pacific and Atlantic oceans. From about the 10th century AD, whaling for right whales only expanded. Today, these animals are under full protection, judging by the latest data, the breeding trends of the genus are positive.

All types of whales, the list of which you can see in this article, are amazing and unique. Take, for example, the pygmy whale. It was named so because of its small size. Usually individuals do not grow in length more than 6 meters. But if you do not take this parameter into account, then otherwise the animal is no different from its relatives.

endangered whales

The family of gray whales is one of the most exterminated at present. These are rather large representatives, 15 meters long, without a dorsal fin. In the 18th century, the population numbered approximately 30 thousand individuals. As a result of active whaling, the number of gray whales by 1947 was reduced to 250 individuals. After that, the family of gray whales was taken under constant protection; today there are about 6 thousand of these animals.

It is impossible not to mention the minke family. These include humpback whales and real minke whales. Both those and others are endangered species of whales. If back in the 30s of our century there were about 250 thousand fin whales in the Antarctic, today this figure is five times less. Of the 100,000 who once lived in Antarctica in the 30s, by 1962 only 1,000-3,000 individuals remained alive. The situation is approximately the same with sei whales and humpback whales, which are under constant protection. The largest representative of striped whales is blue. He is the only whale species that leads a nomadic lifestyle.

Toothed whales: types and description

The suborder of toothed whales has a large number of families. They are united by the presence of teeth, although the sizes, as well as their number, can differ significantly. Almost all representatives have small size body. The only exception is the sperm whale. Of course, oceanic dolphins are the most famous of the suborder of toothed whales. Most of them are small animals.

Easiest for appearance identify the white whale. You can do this by the color of his skin. small, usually up to 5 meters. They are found almost everywhere. Sometimes these whales swim where they cannot live. It is impossible not to single out the only representative of the genus of narwhals - the narwhal. They are somewhat similar to white whales. True, narwhals have a 2-2.5-meter tusk on their heads, which is inherent only to males. The length of the animal is about 5 meters.

Porpoises and dolphins

So we come to the dolphin subfamily. It should be noted that it includes a large number of species and even more subspecies. Only about half of today's known whales. For example, an ordinary brown dolphin or simply a porpoise is usually no more than 2 meters in length. The back of the animal is black, and the belly is almost white. Dolphins for the most part prefer warm waters and temperate latitudes. Often swim far up the rivers. Interestingly, a special race of porpoises lives in the Black Sea.

The following types of porpoises live in different parts of the seas and oceans:

Californian;

• black featherless, etc.

All species differ insignificantly, as well as size. In general, animals, although predatory, are very peaceful. Studies have shown that some species of whales and dolphins have a highly developed brain. What makes dolphins really amazing is their ability to communicate - echolocation. This is a kind of language, most of the sounds of which are incomprehensible to humans even today.

Genus of sperm whales

As noted above, sperm whales are the real giants among all toothed whales. In length, animals can reach about 20 meters. These are gregarious whales that can be found in all the oceans of planet Earth. The exceptions are females and young whales, which prefer to be in warm waters. Today it is not a fully explored species. In particular, it is not known if males return from their distant migrations. Scientists have not yet figured out why they swim so far, although the most likely theory is that they are looking for food. In commercial terms, the sperm whale is very valuable. This became especially noticeable in the years after the Second World War. Near the coasts of Chile and Peru, these animals, in particular, females, were practically destroyed, which seriously threatened the population. Even today, in all the oceans of the world, toothed whales are being hunted and exterminated. Animal species are of no particular importance to humans.

Conclusion

Here we have examined the main types of whales. The names of these animals were assigned by more than one people of the world and not only in the 21st century. Unfortunately, even today there is an active fishery. How many types of whales are left today? About 40, and despite the fact that before there were more than a hundred. It is one thing when this process is controlled, and quite another when there is uncontrolled capture and destruction.

Of course, one can endlessly talk about the fact that insulin and other hormones are extracted from the brain of a whale, and vitamin A is extracted from the liver. In addition, meat is used to make expensive sausages. But all this can be found in nature without destroying different kinds whales and without reducing their population. Well, that's all that can be said about whales and the diversity of their species. For the most part, these are calm animals that rarely attack humans.

From this lesson you will learn about whales and cats, about pinnipeds and proboscis, about bears and martens, and also about what all these dissimilar animals have in common. You will continue your study of mammals and find out how these warm-blooded animals were able to develop such diverse habitats on land and in the aquatic environment. You will learn about the smartest inhabitants of the sea - dolphins, about their ways of communication and group hunting, about how predatory animals differ from herbivores and who is a panda: a raccoon or a bear. In addition, you will be told about the reasons for the ban on whaling, which only three countries in the world have not joined. You will learn about the importance of whalebone and ivory to our ancestors, as well as how the use of plastic saved these animals from complete extermination.

Homework

1. What animals are cetaceans? What is characteristic of them?

2. List the families of carnivores known to you. Which representatives are found in your region?

3. What animals are proboscis? With what detachments known to you are proboscideans related?

4. Name the pinnipeds you know. Which of them are found on the territory of the Russian Federation?

5. Discuss with friends and family why animals as diverse as whales, elephants, and bears are classified as Mammals? How did this class evolve?