By nature of foraging all cetaceans can be classified as either filter feeders or grabbers.
Baleen whales are filter feeders, which catch prey in mass quantities with the help of a filter apparatus (whalebone) and swallow whole batches of filtered organisms. After closing the mouth, the tongue is pressed against the palate and displaces water from the oral cavity outward through the gaps between the plates of the whalebone; small organisms, like a sieve, are retained by the fringe and are pushed into the throat by the movement of the tongue. In those whales that feed on larger pelagic crustaceans ( Euphausiidae, medium and large Copepoda), schooling fish and cephalopods, the mustache is coarser, the plates are shorter and the fringe is thicker (minke whales are planktoichthyophages and microplanktophages). When catching prey, they move impetuously, swallowing food in large portions. On the contrary, those that consume very small, pelagic crustaceans or mollusks are equipped with elastic and long plates with a thin hair-like fringe (smooth whales are microplanktophages). Finally, whales feeding on benthic crustaceans have the roughest and very short baleen with thick fringes (gray whales are benthivorous). They catch prey in the bottom layers or at the bottom, scooping it up together with silty masses (Tomilin, 1954). In the morning and evening, toothed whales feed on crustaceans and cephalopods more intensively than during the day (Nemoto, 1959).
Grabbers include toothed whales; they catch prey, as a rule, by the piece; the nature of their main food also leaves a certain imprint on behavior - the depth of diving, the duration of respiratory pauses, the size of the herd, etc.
Humpback whale(Megaptera novaeangliae)
The largest number of sharp conical teeth is observed in typical fish-eating forms (up to 240 in common dolphins), and the smallest in those that feed mainly on cephalopods (sperm whales, beaked, gray dolphins, narwhals).
Whales are very voracious. Up to 1.5 tons of crustaceans were found in the stomach of minke whales. Whales can satisfy their big appetite only on huge accumulations of food in cold latitudes, where a lot of whales come in the spring-summer half of the year. The food of baleen whales is especially crowded in spring and summer. Crustaceans in cold and temperate latitudes in the zones of the junction of cold and warm currents develop in such numbers that they create brown fields visible at a considerable distance, and close-knit schools of fish (for example, herring, capelin, polar cod) sometimes occupy the sea surface of several square kilometers. The accumulation of food and its nature largely determine the size of herds of cetaceans.
Species composition of the diet each type of described detachment varies depending on geographical distribution, ecological zone and season. In connection with the main food, different species of cetaceans prefer certain zones in the ocean and, as a rule, concentrate in areas of high biomass that develop where there is active water mixing (“polar front”). Some (planktophages - smooth whales) prefer to feed mainly in the open sea, in the surface layers of water on accumulations of zooplankton (small crustaceans and pteropods); others (benthophages - gray whales) feed in areas of shallow depths; still others (ichthyophages - most species of the dolphin family) catch schooling fish both near and far from the coast, sometimes enter large rivers and even climb hundreds of kilometers along them; the fourth (planktoichthyophages - most minke whales) have a mixed diet of crustaceans and fish (rarely cephalopods), which are mined in the surface thickness of the sea; the fifth (sarcophagi, which means meat eaters - killer whales) eat fish and marine mammals, which are usually attacked by a group in any zone of the ocean; the sixth (teutophages - sperm whales, beaked, gray dolphins, etc.) feed mainly on cephalopods, for which they dive for a long time and sometimes to great depths.
Changes in feeding conditions by the seasons of the year cause a sharp fluctuation in the fatness of whales. The fattest whales are at the end of feeding (autumn), and the least fat in winter and spring, during the breeding season in warm waters, when many whales do not feed. Dolphins in our waters are as fat as possible in winter and thinnest in summer (during the breeding season). The different biological state of individuals in certain seasons of the year, the unequal participation of males and females in the rearing and rearing of young animals, and the unequal opportunities for obtaining food in animals of different sexes and ages determine the age and sex differentiation of herds of many species of cetaceans. In baleen whales, differentiated herds are formed only in winter during the breeding season, and in summer, when food is equally available to all individuals in the surface layer, mixed herds are formed (Tarasovich, 1957).
breed cetaceans, judging by the percentage of nursing, lactating and dry females, usually after two years, but some dolphins mate while still lactating and breed annually. Mating of lactating females is much less common in large whales (grey whales, humpback whales and minke whales).
Basic mating season covers 3 months, but some cases occur throughout the year. Widely migratory species (minke whales) breed mainly in winter, in relatively warm waters, and those that do not migrate far (dolphins) breed in summer. In both cases, cessation of nutrition during the rut and childbirth causes less damage to the body, as it is timed to favorable temperature conditions. external environment. Only gray whales have certain places for childbirth. The rut of toothed whales is accompanied by fights between males, resulting in -on the body there are traces of teeth (dolphins, beaked).
well developed single young is born very large - from 1/4 to 1/2 the length of the mother's body. Occasionally, several embryos are found in females; this can be seen as proof of the former prolificity of cetacean ancestors. The largest number embryos in one female reached seven (in a blue whale in 1924/25 in Antarctica with an embryo length from 97 to 135 cm) and six: three cases in a fin whale - one in 1909 in North Atlantic with embryo length from 44 to 89 cm (Haldahe, 1910), another February 24, 1950 in the Antarctic in a female 21.04 m long with embryos from 101 to 332 cm and the third on February 21, 1953 in the Antarctic in a female 21.94 cm long m with the size of two male embryos 238 and 353 cm and four female embryos from 220 to 319 cm.
In large minke whales (fin whales and blue whales), among more than 30,000 embryos studied, twins accounted for only 0.6-0.9%, triplets - 0.018-0.041%. and cases with four and five embryos - 0.006-0.008%. Excess embryos during pregnancy, apparently, are resorbed, and only in the rarest cases can not more than two cubs be fully developed and born. The embryos of baleen whales are most often noted in the right horn of the uterus, and in toothed whales - in the left. Pregnancy different types lasts from 9 to 16 months. Childbirth takes place under water, and the first respiratory act the cub performs at the moment of the first emergence to the surface as unconditioned reflex, in which the stimulus is the sensation of changing the environment (water-air).
The baby will be born tail first. Due to the contraction of the uterus, the most mobile part of the embryo, the tail, is turned towards the genital opening. With this orientation, the embryo passes through the mother's birth canal more easily, since the tail is thinner than the head. The umbilical cord is torn at the very base, where the greatest degree of invagination of the epithelium is noted. The lactation period lasts from 4 (in some dolphins) to 10-13 months (in sperm whales) and sometimes partially coincides with a new pregnancy. Females, judging by observations in aquariums, feed their young with small portions of milk, but often, that is, at short intervals. The calf with the tip of the mouth and, possibly, the tongue tightly captures the right or left nipple, which swell during the lactation period and protrude from both pockets located on the sides of the urogenital fissure. From the first days, the suckling moves next to the female, or slightly behind her. With age, this habit weakens and disappears. The very high nutritional value of milk, in which the fat content reaches 53%, and protein - 13.4%, contributes to the rapid growth of cetaceans during the lactation period. Baleen whales almost double during this period, and toothed whales - by 1/3 of the size characteristic of newborns. By the time of the transition to independent nutrition, the baleen plates of the calf sharply increase (functional jump).
Puberty in cetaceans, it begins at the age of 3 to 6 years, but body growth after that continues for a period that is 1.5-2.5 times longer than the period required for puberty. Achievement full growth, or the so-called physical maturity, in whales coincides with the ossification of all epiphyses of the vertebrae and their fusion with the vertebral bodies in all parts of the spine.
killer whale(Orcinus orca)
The process of ossification of the spine starts from both ends, goes faster from the tail and ends in the thoracic region. Such successive changes in the spine can be used as auxiliary signs in judging the individual age of cetaceans. The age of cetaceans is determined in four ways: 1) by the ovaries of females; 2) along the whalebone plates; 3) ear plugs of baleen whales; and 4) teeth of toothed whales. It is much easier to determine the age by the sex glands of female dolphins.
By whalebone age determine by counting irregularities (“annual steps”) on the surface of the baleen plates, reflecting the seasonal periodicity in the growth rate of the whalebone.
In the first years of the life of baleen whales, the growth of plates from the base outstrips the rate of wear from their tips, and then up to 5–7 “annual steps” can accumulate on the whiskers of minke whales, and up to 15–20 “annual steps” on the whiskers of right whales. In the future, the growth rate and the rate of wear equalize, as a result of which the height of the plates stabilizes, and further accumulation of annual rings stops. Therefore, baleen can serve as an indicator of age only in the first period of the life of whales.
The age of baleen whales is most accurately determined by the layered structure of the ear plugs in the ear canal. Ear plugs vary greatly in shape: their core is laid before the birth of the whale. With age, the ear plug grows in thickness at its proximal end, covering the top of the membranous digital process. Alternating dark and light layers of ear plugs are formed periodically in two (one dark and one light) layers per year. The dark layers consist of degenerated carotene cells of the epithelium of the membranous finger-shaped process protruding into the auditory meatus, and the light layers consist of various fatty inclusions. The rhythmicity of the formation of dark and light layers is explained by the periodic influence of hormones and enzymes in the body of the whale on the degeneration of epithelial cells (Icbichara, 1959) and, possibly, by changes in metabolism due to migration. The inconvenience of this method is the high complexity of extracting ear plugs from the ear canal of animals, although the method of making sections for counting layers is currently simplified (Zemsky, 1960).
In toothed whales - special meaning to determine age, they have concentric layers of dentin in the teeth, reflecting a periodic change in the physiological state of the body, possibly due to seasonal changes in nutritional conditions and reproduction cycles. The layers of dentin deposited after birth are separated from the dentin formed during the embryonic period by a clear neonatal line, which is formed due to a sharp change in nutritional conditions on the verge of the embryonic and lactation periods.
In captive bottlenose dolphins of predetermined age, Sergeant (1959) showed that in dolphins one complete layer of dentin, including light and dark parts, is deposited annually, and the light part is deposited in the spring. However, in the beluga whale and possibly in the pilot whale, two complete dentin layers are deposited each year, and in the pilot whale dark part formed in summer.
In sperm whales, apparently, two complete dentin layers are deposited annually, the counting of which is greatly hampered by the presence of several thinner layers in these layers.
The highest number of layers in the ear plugs indicates that odontocetes and baleen whales live up to 50 years. Harpoons overgrown in the body, some smooth whales and sperm whales were worn up to 40 years, and the oldest tags were removed from 15 fin whales after 24, 25 and 26 years (whales were tagged in Antarctica in 1934 and 1935, and mined in 1959, 1960 and 1961; Brown, 1959, 1960, 1961).
Literature: Professor Tomilin Avenir Grigorievich. Cetaceans of the seas of the USSR, 1962
The huge feeds on the smallest - so you can say about whales. Because whales eat plankton - a kind of living suspension of tiny organisms floating in the water column. But this is true only in relation to toothless, or baleen, whales. Toothed whales have completely different gastronomic preferences. The notorious killer whales have gained fame as ruthless killers, and the sperm whale is able to grapple with the inhabitant of the depths - a giant squid, defeat it and eat it.
Nursing the cubs
Whales are mammals. Females feed their cubs with thick and high-calorie milk, half consisting of fat and protein. The milk of cetaceans is cream-colored, similar in consistency to a paste, and does not spread in water.
The feeding process takes place under water. A newborn kitten must have time to eat and breathe at the same time. He captures the nipple for about 5-6 seconds, the female sends a trickle of milk into the mouth of the offspring by contraction of the muscles, he takes a sip and immediately floats up to inhale the air. "Gymnastics" continues throughout the entire period of milk feeding - this is how a small whale trains the skill of holding its breath. A baby blue whale drinks up to 200 liters of milk per day. Whales begin to feed on their own quite late - for example, the sperm whale remains a "baby" for 13 months.
Two types of food
All whales are descended from common ancestor- mesonychia. 50 million years ago is strange creature, similar to an ungulate wolf, lived along the sea coasts, hunted fish and small amphibians. In search of food, the mesonychia swam further and further, and less and less often went ashore, from where they were driven away by land predators.
Evolution quietly did its job - unnecessary hind limbs disappeared, cartilaginous blades grew on the tail, and the front paws turned into flippers. At some point, whales split into two branches - baleen (Mysticeti) and toothed (Odontoceti). Some began to graze peacefully in the ocean, filtering out plankton, while others turned into fearless and swift hunters.
baleen whales
Baleen whales are called "filterers" for specific way food not found in other warm-blooded animals. Instead of teeth, they have whalebone plates descending from the upper jaw and collected in a kind of "blinds" on the sides of the mouth. The edge of the plates, facing inward, is provided with a thick fringe. The tongue of baleen whales is well developed, mobile and adapted to pulling a mass of small prey into the throat. The head of the filter whale takes up to a third of the total length of its body, and the lower jaw is shaped like a bucket.
The feeding process is as follows: the whale is gaining a full mouth of water, along with the plankton in it. Having closed its jaws, the animal with its tongue, like a piston, squeezes the water out - through the frequent plates of the whalebone. The lips of the whale at this moment are not very tightly closed, and the water, cleared of plankton, goes back into the ocean. All solid inclusions settle on the fringe. The tongue makes a reverse movement and removes from the "filter" everything that has settled on it.
Baleen whale head in cross section
Although, along with plankton, a certain amount of small fish, molluscs, jellyfish, algae and other marine life, their percentage is negligible compared to the mass of the main prey. That is, baleen whales are planktophages.
What does plankton look like?
Plankton (translated from Greek - “wandering”) is the collective name for all living things that soar between the water surface and the bottom. This is a community of small living creatures, ranging from diatoms to fairly large, up to 6 cm long, crustaceans. Plankton in the bulk is not capable of active movement and is carried by ocean currents.
Diversity of plankton The species composition of plankton is heterogeneous - it depends on the season, latitude, water temperature and other factors. Phytoplankton, that is, the simplest algae, keeps in the uppermost layers of the water, closer to sunlight. However, whales are not attracted to algae, they are interested in more high-calorie food, namely zooplankton.
"Pastures" of whales
Zooplankton consists mainly of small crustaceans. Forms huge accumulations in the oceans. Whales are looking for them. And when they find it, they slowly move in the mass of plankton, regularly opening and closing their mouths, like a harvester during harvest.
Whales are herd animals. Having found a feeding place, the whale calls its relatives. His voice sounds with the power of an aircraft turbine and is heard for many hundreds of kilometers. But these cries of concern do not cause people, because sea giants communicate in the infrasonic range (below 50 Hz).
Baleen whales have a number of adaptations that allow them to capture as much food as possible. Minke whales (blue whale, fin whale, etc.) were especially successful in this. Under the lower jaw they have a leathery bag, usually assembled into long longitudinal folds. The volume of this bag can increase several times.
"Bucket" whale-minke. Visible whalebone on the upper jaw Each species of whale has a filtering apparatus "tuned" to a catch of a certain size. Right whales (bowhead, southern, Japanese) feed on tiny, no more than 0.5 cm, crustaceans of the genus Calanus, so their filter is equipped with a thin and frequent fringe, intertwined in a dense network. Krill, the favorite food of minke whales, are crustaceans of the euphausian order, about the size of a finger. Accordingly, the fringe of minke whales is coarser and sparse.
The largest creature on the planet, the blue, or blue whale, feeds fat on krill. The length of this giant can reach more than 30 meters, and the weight can exceed 150 tons. The blue whale catches and sends about 50 kg of krill to its stomach in one go, and its daily ration is 6-8 tons.
Krill Not a krill alone...
The seival, also known as the willow whale, is not content with plankton alone. Sei whales collectively attack shoals of sardine, pollock and other fish, confuse them with tail blows and swallow them. The same fate befalls flocks of small squids.
The humpback whale (Megaptera novaeangliae) is the most versatile hunter of the minke whales. AT warm seas, where there is a lot of plankton, the hunchback feeds like an ordinary filterer. But in the northern waters, the diet of the humpback whale changes dramatically - it turns into an ichthyophage. Capelin, saury, herring and other schooling fish become its prey. A flock of humpbacks operates in a coordinated manner, using rather complex hunting techniques.
toothed whales
Unlike baleen whales, which swallow their prey in bulk, toothed whales grab their prey one by one. The sperm whale and the bottlenose feed on cephalopods. Small toothed whales mainly eat fish. Killer whales prey on warm-blooded - penguins, seals, their flocks attack large whales and tear them apart. In English, a killer whale is called a killer whale, that is, a killer whale.
Killer whale - a thunderstorm of seals sperm whale prey
The most impressive representative of toothed whales is the sperm whale. A mature male reaches 20 meters in length and weighs 50 tons. The prey of the sperm whale to match the hunter is the giant squid of the genus Architeuthis, living at depths below 500 m.
Diving in search of food, the sperm whale is able to hold its breath for up to an hour and a half. The maximum proven depth of this whale is 2 km. sunlight does not penetrate such a thickness of water, so the sperm whale is looking for a prey using echolocation. Loud clicks emitted by him, jamming squid and disorienting them in space. But even a stunned giant squid is a dangerous rival, especially for females and young whales.
Sperm whale and giant squid. Diorama in the Museum natural history, USA
Although the fights of the sperm whale with the kraken take place far from human eyes, it is not difficult to guess that the whale almost always comes out the winner. In the stomachs of sperm whales, whole heaps of "beaks" (squid jaws) are found. The skin of an adult whale is dotted with circles - battle scars from cephalopod suckers.
Not finding squids nearby, the sperm whale preys on other bottom dwellers. Those who hid (octopuses, stingrays and others), the whale scares away, furrowing the silt with its lower jaw, which can open at a right angle. Nature provided the sperm whale with a cunning bait - White skin around its mouth is inhabited by phosphorescent bacteria. Deep-sea creatures willingly swim into the light - and get directly to the dinner of the sperm whale.
The blue whale (blue whale, or blue whale) is the largest animal on the planet. Since the blue whale breathes with lungs and feeds its children with milk, it is a mammal, not a fish. There are only three species - pygmy, northern and southern blue whales, which differ slightly from each other.
Blue whale anatomy
The blue whale, like all mammals, breathes exclusively with lungs. Of the senses, blue whales have very developed hearing and touch. The blue whale, which is the largest living creature on planet Earth, has the same amazing dimensions of internal organs - for example, one tongue of an adult can weigh more than 4 tons! The pulse of whales is very low - 5-10 beats per minute, and the heart weighs a whole ton! This is an absolute record among all living beings. In length, the whale can reach up to 33 meters, and the weight of an adult is approximately 150 tons! In blue whales, females are larger than males.
Style: Blue whale
Genus: Stripes
Family: Striped
Class: Mammals
Order: Cetaceans
Type: Chordates
Kingdom: Animals
Domain: Eukaryotes
Blue whales have a very large head and a long, slender body. On the back of the head is a blowhole, which is formed by the two nostrils of the animal. On the lower part of the head of the blue whale there are stripes that form from the folds of the skin. They help the whale stretch its pharynx when it opens its mouth to take in food. At this point, the whale's mouth can stretch 1.5 times! In total, blue whales can have from 55 to 90 such folds.
Where does the blue whale live?
The blue whale is cosmopolitan. This means that its habitat extends to the entire world ocean, but somewhere, due to cold currents, the whale cannot be all year round and migrates, and somewhere it is quite comfortable all the time - for example, in the Indian Ocean. Most often they are seen in Ceylon. A large number of people are sure not best place for blue whale watching than in Sri Lanka.
What does the blue whale eat?
The blue whale's favorite food is krill (large aggregations of crustaceans) and plankton. The whale does not eat fish at all, even if it accidentally absorbs it, it is exclusively along with a large amount of plankton and krill. He eats simply by opening his huge mouth and swimming forward, collecting water with food, and then the water flows out through the whalebone.
Blue whale lifestyle
Unlike other whale species, the blue whale can be called a loner. Sometimes some individuals form small groups but usually they stay alone. The blue whale prefers to lead a daytime lifestyle - this is evidenced by numerous studies.
Blue whale breeding
Reproduction is a sore subject for the blue whale. It reproduces extremely slowly, so slowly that some scientists tend to think that the increase in the birth rate of blue whales is not able to cover their mortality. The growth of blue whales is the slowest of all whales. The blue whale is monogamous. The male, having found his female, protects her and never moves away from her. The female can become pregnant once every two years, after which she bears a cub for another year.
The cub is born weighing about 2 - 3 tons and 6-9 meters long. It feeds on mother's milk for about 7 months. Sexual maturity is reached at about 10 years of age. At the age of 15, the blue whale is already fully formed physically and is gaining its weight and body length. Whales live for quite a long time - about 90 years.
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Recently, a program about the life of whales was shown on TV. I was so engrossed in watching that I didn’t even notice how two hours flew by. Although these marine animals are so huge, they are not at all enemies to humans. They live mainly in groups. Now I will tell you a little about how whales live and what they eat.
whale life
It turns out that whales, like dolphins and other representatives of cetaceans descended from land animals. It seems that whales have absolutely nothing to do with them, and are more like some giant fish. Of all the animals The hippopotamus is considered the closest relative of the whale..
In nature, there is no mammal whose size is larger than the size of a whale. They are warm-blooded unlike fish. The blue whale is the most major representative these inhabitants sea depths. Its length reaches 33 meters. You can compare it to a small ship. Distinguishes whales from fish presence of lungs. For one breath / exhalation, the air exchange in whales is 90%. Thanks to this feature, they can not rise to the surface of the water for up to 40 minutes.
Whales well developed sense of touch. Individuals communicate a lot between themselves. The echolocation apparatus helps them with this. Some species of whales in cold weather go to warm waters where they produce offspring.
whale diet
The basis for feeding whales is plankton. Plankton are called small crustaceans. In addition, other inhabitants of the deep sea also get into the food of whales:
- fish;
- small marine animals;
- squids;
- cuttlefish.
There is the only species of cetacean mammals that, in addition to small fish and plankton, can eat a seal, a penguin and even a dolphin. It's about about the orca. It is not difficult to recognize her in black and white color. There are about 80 known various kinds whales. Many of them are listed in the Red Book. In almost all countries of the world, hunting for these mammals is prohibited. I hope that someday I will be lucky enough to see a whale not only on TV.
