Lifespan. How long do whales live? The great blue whale is the giant of planet Earth. Description and photo of a blue whale Where does the blue whale live
From the order of cetaceans, belonging to the baleen whales. The largest whale, the largest living animal, and also probably the largest animal that has ever lived on Earth. Its length reaches 33 meters, and its weight can significantly exceed 150 tons.
Appearance and structure
The physique is proportional, the body is well streamlined. The head is convex from the sides, but blunt in front. The respiratory opening (blowhole) is surrounded in front and on the sides by a ridge that turns into a ridge, which, gradually lowering, ends at the end of the snout. The eyes are small, located slightly behind and above the corner of the mouth. The length of the eye slit is 9-10 cm. The lower jaw is strongly curved to the sides; when the mouth is closed, it protrudes in front of the snout by 15-30 cm. On the front of the head and lower jaw there are several dozen short (15 mm) hairs, the number of which varies.
The miniature dorsal fin is set far back, its height is only about 30 cm and can have a variety of shapes (with a rounded end, triangular, etc.). The pectoral fins are narrow, pointed and somewhat shortened (1/7 - 1/8 of the body length). The width of the caudal fin with a small notch in the middle is equal to 1/4 of the body length. The head is wide on top, U-shaped, with convex edges to the side. There are 70-114 longitudinal skin “stripes” on the abdomen, an average of 80. The depth of the thoraco-abdominal stripes is up to 2 cm, the width is about 5-6 cm. The longest ones reach almost to the navel.
The body of the blue whale is dark gray, with a bluish tint, mottled with light gray spots and a marbled pattern. The head, lower jaw and chin are the same color. There are more spots in the back half of the body and on the belly than in the front and on the back. The belly may be yellow or mustard in color. The heart weighs more than half a ton. The diameter of the aorta reaches the diameter of a small bucket, and the lungs can hold up to 14 m3 of air.
Behavior and lifestyle
In general, the blue whale is more solitary than all other cetaceans. The blue whale does not form herds; it is predominantly a solitary animal, although sometimes blue whales form small groups consisting of 2-3 heads. Only in places with particularly abundant food can they form larger aggregations, divided into smaller groups. In such groups, whales stay scattered, although the total number of such aggregations of blue whales reaches 50-60 animals.
The blue whale, swimming near the surface of the water, is not nearly as maneuverable as some other large cetaceans. In general, its movements are slower and, according to scientists, more clumsy than those of other minke whales. The activity of blue whales at night has been poorly studied. Most likely, he leads a diurnal lifestyle - this is evidenced, for example, by the fact that whales off the coast of California almost stop moving at night.
The blue whale dives quite deeply, especially if it is very frightened or injured. Data obtained by whalers using special instruments mounted on a harpoon showed that a harpooned blue whale can dive up to 500 m, and according to American data, the whale can dive even up to 540 m. Typical dives of a feeding whale rarely exceed 200 m, and more often no deeper than 100 m. Such dives last from 5 to 20 minutes. A grazing whale dives quite slowly - it takes about 8 minutes to dive to 140 m and then ascend. After surfacing, the whale's breathing quickens up to 5-12 times per minute, and a fountain appears each time. Rapid breathing continues for 2-10 minutes, after which the whale dives again. Pursued by whalers, a whale vomits under water much longer than usual, up to 50 minutes.
After a long and deep dive, the blue whale makes a series of 6-15 short surfaces and shallow dives. Each such dive takes him 6-7 seconds, and a shallow dive takes 15-40 seconds. During this time, the whale manages to swim 40-50 m, shallow under the surface of the water. The highest dives in the series are the first after rising from the depths and the last (before diving). In the first case, the whale, slightly bending its body, first shows the very top of its head with its blowhole, then its back, dorsal fin and, finally, its caudal peduncle. Going into the depths, the blue whale strongly bends its body, tilting its head down, so that the highest point is the part of the back with the fin, which is shown when the head and front of the back are already deep under water. Then the “arc” of the back becomes lower and lower, and the whale disappears without showing its tail. A diving blue whale rarely shows its tail fin - in about 15% of diving cases. Observations of blue whales off the southern coast of California have shown that they spend 94% of their time underwater.
Over a short distance, a blue whale can swim at speeds of up to 37 km/h, and in exceptional cases even 48 km/h, but it cannot maintain this speed for a long time, since it places too much stress on the body. At this speed, the whale develops power of up to 500 horsepower. A grazing vomit moves slowly, 2-6 km/h, during migrations it moves faster - even up to 33 km/h.
The blue whale breathes 1-4 times per minute in a calm state. Research in the 1970s showed that the breathing rate of blue whales (and minke whales in general) was highly dependent on the size and age of the whale. Young whales breathe much more often than adults - for example, when surfacing after a deep dive, the frequency of respiratory acts (inhalation-exhalation) in a blue whale 18 m long was 5-10 in 2 minutes, while in an adult 22.5-meter vomit - 7 -11 times in 12.5 minutes. The breathing rate of whales of this size that did not dive was 2-4 and 0.7-2 times per minute, respectively. An adult blue whale, pursued by whalers, breathed (gave a fountain) 3-6 times per minute.
Nutrition
The largest animal on earth consumes about 1 million calories per day. This is approximately 1 ton of krill, which constitutes the main diet of the blue whale. In general, the blue whale is a typical plankton eater: it feeds on crustaceans in the upper layer of water, diving under water for 10-15 minutes. The crustaceans on which it feeds are concentrated in special areas called feeding fields. In such places you can see several whales at once, although they usually do not gather in groups of more than 3 individuals.
Fish, if it plays any role in the diet of the blue whale, is very insignificant. Soviet sources indicated that the blue whale does not eat fish at all; other sources more definitely indicate that it does eat fish. Most likely, the ingestion of fish and other small marine animals occurs accidentally, when eating masses of krill. It is also possible that the predation of small schooling fish and small squid observed in the western Pacific Ocean is caused by the absence of large aggregations of planktonic crustaceans. In addition to a small amount of small fish, small crustaceans other than krill were found in the blue whale's stomach.
The blue whale feeds in the same way as other minke whales. A grazing whale swims slowly, opening its mouth and taking in water with a mass of small crustaceans. The stripes on the throat allow the whale's mouth to stretch very strongly, and the movable articulation of the lower jaw bones also greatly contributes to this. Having scooped up water with crustaceans, the whale closes its mouth and squeezes the water back through the whalebone with its tongue. In this case, plankton settles on the fringe of the baleen and is then swallowed.
The huge lower jaw, filled with water and food, is so heavy that it is sometimes difficult for the blue whale to move it to close its mouth. Measurements of a 150-ton blue whale with a length of 29 m showed that its mouth could hold 32.6 m³ of water. Therefore, often a blue whale, having filled its mouth with food, turns over on its side or even on its back, and then the mouth slams shut on its own under the influence of gravity. Due to its enormous size, the blue whale is forced to consume a very large amount of food - per day it eats, according to various sources, from 3.6 to 6-8 tons of krill, and it is estimated that the number of individual crustaceans in this mass reaches 40 million. In general , a blue whale requires approximately 3-4% of its body weight to feed per day. The aforementioned whale, with a mouth volume of 32.6 m³, could capture over 60 kg of crustaceans at a time at the usual density of krill in the ocean. The tightly packed stomach of a blue whale can hold up to a ton of food.
Whale songs
Leading a solitary lifestyle, whales have developed their own way of communication, with the help of which they communicate with each other across vast distances of up to 1600 km. These are the famous whale songs, the volume of which reaches 188 decibels. The meaning of these songs is not fully understood, but scientists have noticed that whales “sing” during the breeding season, so perhaps singing is somehow connected with the family functions of animals. These songs last up to half an hour.
At first it was believed that only males sing, but there is evidence that female blue whales also sing for their babies. The sound-reproducing system in animals is located in the front of the head and serves as a lens that captures and reproduces sounds. Since whales are practically blind and have no sense of smell, sound is the only means of communication with other individuals, and the only way of contact with the outside world. Therefore, whales are constantly busy analyzing surrounding sounds.
Oceanographers have collected and analyzed thousands of recordings of blue whale "songs" that have been documented by a variety of instruments over the past 45 years. It turned out that slowly but steadily, by fractions of a hertz per year, the tonal frequency of sound is decreasing. This happens regardless of the ocean where the animals live. But, for example, in most of the whale populations surveyed near California, the sound frequency of songs has decreased by 31% since 1965.
Among the possible reasons for this phenomenon, which experts consider in an article published in Endangered Species Research, are a reaction to changes in the composition of water in the ocean, as well as simply the desire of young whales to imitate the timbre of older ones, in which it decreases with age.
The most plausible option and at the same time the most sad one is that due to the fatal decrease in the number of blue whales, they now need to send their “messages” more far away, and low-frequency sounds, as is known, travel further in the ocean.
Reproduction
The peak of mating for blue whales occurs in winter: in January in the northern hemisphere and in July in the southern hemisphere. The body length of newborns is from 6 to 8.8 m, more often 7-8 m, with a weight of 2-3 tons. A strong variation in the size of embryos obtained at the same time indicates that mating periods are extended over almost the entire year. An analysis of the size of embryos in Antarctic catches showed an average increase in their body in November by 35 cm, in December by 56, in January by 72, in February by 92 and in March by 79 cm (Tomilin, 1957). Apparently, the growth rate of the embryos gradually increases, but towards the end of uterine life it slows down somewhat.
Pregnancy lasts a little less than a year (about 11 months). Usually one cub is born; cases of multiple births are rare. According to the International Whaling Statistics (ISS), among 12,106 Antarctic embryos, there were 77 cases of twins, five cases of triplets, one find with five and one with seven embryos. Of the twin embryos, as a rule, only one develops to the end, the rest die and are resorbed. During the 7-month lactation period, the cub, feeding on very fatty milk (34-50% fat), grows up to 16 m and weighs 23 tons, and at the age of 19 months it reaches 20 m and weighs 45-50 tons; medium individuals (23.7-24 m) weigh 80-85 tons, and large ones (30 m) - 150-160 tons (Wheeler a. Mackintosh, 1929; Krogh, 1934; Ruud, 1956). Puberty occurs at 4-5 years, as evidenced by 8-10 layers in the ear plugs, which are used to determine age. Females at this time reach a length of 23 m. They reach full growth and physical maturity at a body length of 26-27 m, which probably happens at 14-15 years.
The average daily weight gain of sucklings, according to zootechnical calculations (Tomilin, 1946), reaches 81.3 kg with a daily consumption of 90 kg of milk. Puberty occurs at 4-5 years, when 8-10 layers appear in the ear plugs, which are used to determine age (Nishiwaki, 1957); at this time, the length of southern females reaches an average of 2-3.78 m, northern ones - 23 m, and the average weight of the testes of males is 10 kg (Ruud, 1950, 1957). Females usually breed every two years. The strong variation in the percentage of pregnant females among sexually mature ones (from 20 to 61%: Laurie, 1937; Ottestad a. Ruud, 1936) depends on the accuracy of registration of embryos at whaling bases and on the number of individuals studied (with less material, larger deviations are possible).
Females reach physical maturity when 11-12 scars of the corpus luteum accumulate in the ovaries; this occurs at 14-15 years of age, and possibly at an even older age, with average body lengths of 26.2 m (Laurie, 1937), 26.5 m (Brinkmann, 1948) and 26.67 m (Peters, 1939 ). The minimum size of physically mature Antarctic females is set at 24.7 m, and for males - 22.3 m. A female with 41 scars of the corpus luteum (18 in one ovary and 23 in the other) already had signs of menopause, and with 35 scars was without such signs . The oldest female in the North Pacific has only 25 scars (Omura, 1955).
Number
The initial number of blue whales, before the start of intensive fishing, was estimated at 215 thousand heads. According to other sources, it could be even higher, up to 350 thousand. The first bans on blue whale fishing in the Northern Hemisphere date back to 1939; they affected only certain areas. Fishing was completely banned in 1966, but the ban did not immediately affect pygmy blue whales, which continued to be caught in the 1966-1967 season.
The current population of blue whales is difficult to estimate. The reason, perhaps, is that blue whales have not been studied very actively for decades - for example, according to authoritative sources in 1984, the International Whaling Commission has practically not been involved in counting the number of these whales since the mid-1970s. In 1984, it was reported that no more than 1,900 blue whales lived in the Northern Hemisphere, while in the Southern Hemisphere there were about 10 thousand, half of which were of the dwarf subspecies.
According to some data, there are now between 1,300 and 2,000 vomit whales in the entire world’s oceans, but in this case, the number of these whales is even lower than 40 years ago, despite the complete lack of fishing. Other sources give more optimistic figures: 5-10 thousand vomits in the Southern Hemisphere and 3-4 thousand in the Northern Hemisphere. The question of the quantitative distribution of the world population of blue whales in individual areas is also not fully clarified.
A number of sources indicate that there are from 400 to 1,400 blue whales in the Southern Hemisphere, about 1,480 in the North Pacific Ocean, and the number of blue whales in the rest of the Northern Hemisphere is unknown. Regarding the Southern Hemisphere (more precisely, the Southern Ocean), other figures are indicated: 1700 heads with a 95% probability that this number is between the two extreme values of 860 and 2900. Moreover, in the Southern Hemisphere, according to the International Whaling Commission, there are 6 herds blue whales The southern subspecies of whales, which became the main target of whalers in the 20th century, remains, according to 2007 estimates, only 3% of the 1914 population.
The growth of the blue whale population is slow, but in some places, for example, in areas near Iceland, the increase after the fishing ban reached 5% per year. American scientists who conducted a detailed study of the cetacean population off the US Pacific coast noted that the number of blue whales in these areas tended to increase throughout the 1980s. However, the same study concluded that there is no data on population growth in the Pacific Ocean as a whole. There are legitimate concerns that the blue whale population may never recover to its original numbers.
Whales are very smart animals. Their incredible intelligence and friendly nature have made whales very popular and interesting animals for science. Scientists generally believe that the brain of whales is more similar in capabilities to humans than the brain of any other animal.
Some structural features of whales have greatly interested doctors. Thus, whales do not have brain hemorrhages, due to the fact that in their heart there is a special shunt connecting two large arteries, which provides reliable protection against blockage of blood vessels, and as a result, against heart attacks.
The whale eye is also of interest to scientists. Firstly, because its size allows you to see what is impossible to see in the eye of a person or other animal. Secondly, the blue whale can dive underwater to great depths, and the structure of its eye is such that it can withstand enormous pressure. Having learned this secret, a person will help patients with glaucoma associated with impaired intraocular pressure.
A whale, and not an ordinary one, but a blue one (Balaenoptera musculus). It is a mammal and belongs to the minke whale family, leading the suborder of baleen whales. The predominant color on the body is dark gray, which becomes lighter towards the ventral part. However, one cannot help but pay attention to the rich blue tint, which was the main reason that this whale began to be called blue. In addition, the body has a light gray or marbled pattern, which often contains bright white spots.
The blue whale is a rare, unique animal that has been practically exterminated over the past centuries. It is for this reason that over the last century hunting it has been banned in almost all oceans, as well as in Antarctica.
Basic data
The largest whale on earth is the blue one. It has up to four hundred pairs of dark black triangular plates on each side of its jaw, which can be up to one meter long. His mustache fringe, like his palate, is black. Its structure is coarse and thick and can reach 40-45 mm. The palate in the anterior part is narrowed and intersected by a single longitudinal groove. The dorsal fin is located in the back of the body, and due to its small size, it helps the blue whale to successfully maneuver at high speed, even despite its impressive size. At the same time, the pectoral fins, which perform similar functions, are, on the contrary, elongated. They can reach more than 10% of the entire body length of a blue whale.
Despite the fact that these whales are the largest representatives of their genus, among them there are individuals that are truly impressive in their size. Thus, the largest blue whale reached a length of 33.27 m and weighed 176.762 tons. It was caught near the South Shetland Islands. The average length of male blue whales is 24 meters. At the same time, individuals living in the northern hemisphere are slightly larger - 28 meters. On average, their body weight reaches 120 tons.
At the same time, a hidden grace is visible in his appearance. The head, despite its significant convexity, is slightly blunted in front. The respiratory opening is surrounded by a ridge that smoothly turns into a ridge, the height of which gradually decreases.
Structural features
The eye slit of the blue whale does not exceed 10 cm, due to which they remain practically invisible against its general background. They are located slightly behind and above the corners of the mouth. The lower jaw is strongly curved to the sides; when the mouth is closed, it protrudes beyond the upper jaw by more than 20-25 cm. At the same time, the front part of the head and lower jaw bear many short hairs, the number of which varies, and the length does not exceed 15 mm.
The length of the throat-abdominal stripes ranges from 70 to 120 cm. Their width does not exceed six centimeters. The longest of them can reach almost to the navel.
Like most individuals that prefer to live at great depths, the largest whale in the world, the photo of which is given in this article, has a layer of fat, which not only serves as a reserve source of nutrients, but also protects the body from hypothermia, maintaining a comfortable temperature. Moreover, the thickness of their blubber (tissue filled with fat) on the side parts of the body near the tail is only twenty centimeters.
Distinctive features
The largest whale (blue) is divided into three main species:
- dwarf;
- northern;
- southern.
Moreover, despite the fact that they are practically the same in appearance, each of these species prefers water with different temperatures - from icy to tropical.
The internal organs of the blue whale are fully consistent with its impressive size: the liver weighs almost a ton, the heart weighs up to three tons, its stomach holds several tons of food at once, and the open mouth area is about 24 meters, as a result of which the hunting process is significantly simplified.
Nutrition
Despite its impressive dimensions, the blue whale cannot be called the most dangerous aquatic predator, because it completely lacks teeth. It eats all kinds of living creatures, the size of which does not exceed 6 cm. In most cases, its daily diet consists of crustaceans and small fish that fall into its mouth while hunting for crustaceans.
Since the length of the blue whale's head is approximately 1/3 of the length of its body, it is not surprising that its mouth resembles a huge container consisting of many horny plates. It was they who received the name whalebone, the fishing for which was previously widespread. They grow on the palate and are similar in structure to a sieve. Having opened it, it swims at high speed through places where prey accumulates, after which, closing its mouth, it forcefully pushes water through the structure of the whalebone with its tongue, as a result of which all the food remains in the mouth, and the water is pushed out through a special hole in the upper back.
Reproduction
Sexual maturity in a blue whale occurs between 4 and 6 years. By this time, females reach a length of 23-25 meters.
The largest whale in the world carries its calf for one year. A newborn blue whale averages about 7 meters in length and weighs several tons.
Due to the fact that the largest whale is also one of the fastest growing animals, by the end of the first year of life the weight of its calf reaches 25-30 tons. The main source of nutrition for the baby during this period is mother's milk, the daily norm of which is approximately 100 liters. In addition, it is noteworthy that if the mother wants to praise the calf, she touches it with the tip of her nose, thereby once again proving that despite the fact that in the course of evolution they began to live under water, blue whales are still mammals.
Habitat
The largest whale in the world (photos allow you to imagine its power) prefers to live alone or in small family groups. They are found in the waters of both the Northern and Southern Hemispheres, but as a result of whaling, their numbers have decreased so much that they are rarely seen.
Previously, they were found in almost all oceans, but today they can most often be seen in the Chukchi and Bering Seas, as well as in areas of tropical islands.
However, they are almost impossible to find in tropical waters. Whales go to European latitudes for the winter and spend the summer in Antarctica.
Biological features
Despite the fact that the largest whale (blue) lives in water and has a fish-like body outline, it is a mammal. As a result of the many millennia that blue whales spent in the water, they became similar in shape to fish, but their lifestyle and body structure remained similar to land animals.
The largest whale, the photo of which is simply mesmerizing, feeds its young, which are born alive and do not go through the formation stages inherent in fish, with mother's milk. Newborns remain close to their mother, who takes care of them, for quite a long period.
In addition, the structure of the blue whale contains certain features that allow it to be classified as a mammal. For example, the fins, which have an internal structure, resemble a human hand, and on the body of some individuals there are even bones in the places where the hind legs of land animals are located.
The uniqueness of blue whales
The largest whale (blue) is found almost anywhere on the planet - from the Arctic to the Antarctic, but there are so few individuals left that they require constant human protection. Over the past centuries, they were mercilessly exterminated for the sake of oil and valuable whalebone, as a result of which they were almost completely destroyed. Despite the strict ban regarding the catch of this unique animal, a significant increase in the number of blue whales has not yet been recorded.
Scientists classify the blue whale, also called the puking whale, as a baleen whale. The length of this sea animal reaches 33 meters, and its weight sometimes exceeds 150 tons. Currently, he is considered the largest earthly creature. Despite their enormous size, they feed on crustaceans, plankton, krill, and small cephalopods. The giant swims slowly, taking water into its mouth, the volume of which is about 23 cubic meters. The whalebone plates form a remarkably efficient filtering apparatus, through which food is filtered and excess water goes into the ocean. For those who want to know in more detail how the blue whale lives, which are sometimes very diverse and similar to science fiction, it is not so easy to find the necessary materials. The life of this giant has not yet been sufficiently studied, and many data need to be verified.
The blue whale has three subspecies - northern, southern and dwarf. Rare, but still found in India. The blue whale can be considered one of the longest-livers of our planet. On average, its lifespan is about 80 - 90 years, sometimes there are references to the fact that individual specimens were able to live up to 110 years.
Blue whales swim in the ocean in small groups of 2 - 3 individuals. Many adult animals are loners. Sea giants are monogamous; if they form a pair, they stay for life and are never separated. The male always stays close to the female and tries not to swim far from her. In places with an abundance of food, whales gather in large numbers, but even there they swim very scatteredly.
The animal's movements are slow, apparently due to its large body size, it maneuvers poorly and is rather clumsy. Until now, its activity at night and in the evening has been almost not studied; it is assumed that it leads a diurnal lifestyle and moves little at night.
What constitutes the basis of the giant’s diet has been fully studied. This is plankton, crustaceans not exceeding 6 cm in size, from the order of euphausiaceae, which often form huge aggregations - krill. Small fish and small squid are swallowed accidentally during feeding and have no significance for the whale’s nutrition. The sea animal eats plankton along with water, and then closes its huge mouth and squeezes out the remaining water with its tongue through the whalebone. Sometimes it is very difficult for him to “slam it shut”, since, according to measurements, the volume of such water in a 150-ton bottle is 32.6 cubic meters. Often the blue whale does not have enough strength; with its mouth full of food, it is forced to roll over on its side or even on its back, then under the pressure of the sea depths its mouth slams shut. A fully filled stomach of a sea giant can hold up to one and a half tons of food.
Interesting facts about whales include the following information. For about eight months a year, blue whales eat almost nothing; they live on previously accumulated reserves - they use up fat. But in the summer they feed actively, absorb food almost non-stop and quickly restore normal weight. To do this, they swim to the cold, but food-rich Arctic waters of the Southern Hemisphere and feed intensively there for 120 days. In warm tropical latitudes, whales' stomachs are usually empty.
Reproduction
The blue whale has the lowest natural growth rate of all baleen whales. At one time, ketologists (scientists who study cetaceans) believed that the increase in their population could no longer compensate for the decline. In this regard, on February 19, 1986, the International Whale Commission introduced a complete ban on fishing for all species of these marine animals.
Female bleachers give birth to cubs every two years. But recently, due to their small numbers, married couples can form much less frequently. This leads to a decrease in the likelihood of having offspring. The duration of pregnancy is not precisely established, on average it is from 10 to 12 months. Most often, one cub is born, whose body length exceeds 6 meters and weighs 2 - 3 tons. Sometimes there can be twins.
Female blue whales have several embryos at the beginning of pregnancy, the maximum established number of embryos is 7. But in the later stages, most of them resolve, which is typical for many cetaceans. This is an atavism, the legacy of land ancestors who had large offspring.
Bulval females feed milk to their young for the first 7 months. During this time, the “baby” manages to grow up to 16 meters, which is comparable to the size of an adult male sperm whale. Its weight can reach 23 tons. Every day a small whale receives 90 liters of milk, and its weight, on average, increases by 44 kg. The fat content in mother's milk reaches 50%, and the amount of protein and fat together makes up half of the total weight. Therefore, with such nutrition, the cub at the age of one and a half years reaches a mass of 50 tons and grows up to 20 meters in length. Physical maturity in buvals occurs after 15 years.
Short but interesting
In the old days, legends were made about mysterious sea animals and stories were told about them. Many of them were quite fantastic. In those distant times, people believed that it was possible to live in the stomach of this huge creature. In fact, the throat opening of a blue whale is comparable in size to an ordinary saucer. Theoretically, a sperm whale can swallow a person; the size of its throat may well allow this. For many people, the following facts may seem surprising or incredible:
Over the years, the number of blue whales has been gradually decreasing. But many scientists believe that they can still be saved from complete extinction. Famous politicians, actors, and public figures are working on the possibility of preserving these, now rare, marine ones. Thanks to the systematic study of these giants by ketolags, many people learned what it is like, a blue whale, interesting facts about which are replete with incredible data.
Blue whales are the largest animals on our planet: adults range from 24 to 30 meters in length, while females can exceed the size of males by up to 10 meters. In the XX century. they were almost completely exterminated due to commercial fishing. And only after a general ban on the destruction of whales did their numbers begin to gradually increase.
The upper part of the whale is a mottled blue-gray color, while the lower part is light gray or yellow-white. The yellowish tint of the animal's abdominal part is given by growths of microscopic unicellular seaweeds called diatoms. These plants are common in cold sea waters.
It is officially believed that the largest individual was a female, which was caught by whalers in the last century, 23 m 58 cm long. These animals can weigh up to 200 tons. For comparison, the weight of an African elephant is 7.5 tons. The heart of a blue whale is the size of a car, the beat of which can be heard 3 kilometers away. One of the species is the pygmy blue whale. They are three meters shorter than their larger relatives.
These animals have one incomparable quality: blue whales are the loudest animals on earth. The volume of their call signs reaches 188 decibels, which is significantly higher than the sound of a jet engine - 140 decibels. An animal can hear the song of a relative at a distance exceeding 1.5 thousand km.
In addition to their enormous size, the distinctive features of blue whales are a relatively small dorsal fin, a rounded part of the front of the skull and about 90 longitudinal grooves on the belly, reaching the navel.
Features of communication
Blue whales travel alone for most of their lives, sometimes in groups of 2-3 individuals. Large flocks, which may include 60 animals, have been recorded in places where food accumulates.
But there is one “but” here. The blue whale has the strongest voice of all animals, the low frequencies of which can spread in the deep-sea environment for many hundreds and even thousands of kilometers. Therefore, what may seem to people like “solo” sailing, in reality, is not so. Thanks to the ability for such negotiations, a solitary whale is often in close contact and communication with its relatives.
Nutrition
Whales feed by diving every 10-20 minutes to a depth of about 100 meters. The stomach can hold about one ton of krill at a time. Its requirement for krill is about 4 tons daily during the summer feeding season.
In the mouth there is a so-called “whalebone” of black color. These are horny plates hanging from the upper palate, 300-400 pieces each. from each side. The length of the plates ranges from 50 cm in front to 100 cm in the back. To feed, the animals straighten the “whalebone” in their throats and take in water with krill, sifting it through the horny plates. The water is then released through the baleen and the remaining krill in the mouth is swallowed.
Life cycle
The female usually gives birth to one kitten every two to three years. Currently, this birth rate exceeds the rate of destruction of animals during hunting, which continues to this day.
At birth, the baby whale is the largest newborn animal on earth: it is 8 meters long and weighs about 4 tons. In this case, the female’s pregnancy lasts a year, and usually one baby is born. The cubs grow at a rate of 90 kg per day. Childhood ends at 7-8 months, after the animal reaches 15 m in length and learns to swim independently. Animals reach maturity at 5–10 years.
The growth rate of the blue whale is also amazing and is the highest in the animal kingdom. In just a year and a half, the size of tissues increases several billion times.
Like other cetaceans, blue whales do not have teeth. Therefore, it can be difficult for scientists to determine the age of an animal. It is believed that their average lifespan reaches 50 years, some individuals can live up to ninety, and the oldest animal is considered to have died at the age of 110 years.
Extermination of whales
Before the start of active whaling, the population of blue whales exceeded 250 thousand individuals. But in the 20th century. due to merciless hunting they were almost exterminated. Between 1904 and 1967, more than 350 thousand individuals were killed in the southern hemisphere alone. Many animals also died at the hands of Soviet whalers between 1960 and 1970.
The whales suffered especially hard in 1931, which marked the heyday of the fishery. This year, in just one whaling season, more than 29 thousand blue whales were killed. And only in 1967 the situation began to improve, when the world community stood up to protect animals, and whaling was banned.
Population today
Today, blue whales are distributed throughout the world. Their habitat includes all the world's oceans, with the exception of the Arctic Ocean. Blue whales are one of the most rarely seen species of cetaceans. Scientists still haven’t decided how many there are on earth. Their number ranges from 10 to 25 thousand.
One of the many populations of these animals that continues to grow at an encouraging rate is the population of whales that live in the North Pacific Ocean near the US state of California. The number of its representatives reaches 2 thousand.
This species, known as pygmy whales or pygmy whales, lives mainly in the Indian Ocean. Recent research suggests that these animals live in other areas of our planet.
Blue whales prefer to swim in deep ocean waters. In summer they migrate towards the poles, into cooler waters. In winter, the animals swim back towards the equator to warm waters to breed. Due to the fact that the seasons in the northern and southern hemispheres are opposite in time, populations of representatives living in different parts of the planet do not communicate or mix with each other.
Danger to whales
Most biologists have concluded that blue whales are the most endangered of all cetaceans. A serious danger for them is:
- water pollution with chemicals;
- a violation of the natural sound balance, due to which they are unable to find a mate;
- loss of permanent habitat;
- collisions with ships and entanglement in fishing gear.
Climate change could have a significant impact on food supplies, as global warming could shift the pH balance of seawater to acidic levels. This will affect the number of krill that the blue whale feeds on.
Due to climate changes in the frontal zones, the habitats of blue whales, there is a shift further south. In frontal zones, water can rise from the depths, bringing with it gigantic amounts of nutrients. This stimulates the growth of phytoplankton, and also creates conditions for the growth of populations on which the animals feed.
As a result of the migration of frontal zones over a distance of 200-500 km, blue whales are forced to migrate further to feed. Over time, such movements can significantly reduce the body's energy reserves and shorten the feeding seasons. As frontal zones move south, they reduce the areas where species of animals that provide food for blue whales can develop.
