Marine mammals. Why are sea animals able to stay underwater for a long time? Enemies in nature and threats from humans

Chapter seven. Deep sea diving

Habitat in aquatic environment creates a number of difficulties for air-breathing animals. Their breathing is limited external conditions and requirements that land animals do not know. Although dolphins are everywhere, although they are domesticated, almost nothing is known about the nature of their respiratory function. But it must be controlled in a special way, otherwise their life in water would be impossible.

Lawrence Irving, 1941

How extremely mobile deep-sea squids get into the sperm whale's mouth - whether it lures them or pursues them - we do not know. But we know very well that the sperm whale searches for them at a depth of up to 1.2 km, and even deeper, and it can stay there for much more than an hour. For a mammal that is descended from land animals and breathes air, such a lifestyle is extremely difficult.

Some of the relatives of the sperm whale, representatives of the beaked whale family, although they are smaller in size, are in no way inferior to their giant relative in the art of diving to depths. Small cetaceans, we believe, do not reach such depths, but there is evidence that the common dolphin, well known for its habit of “riding” waves emanating from the bow of a ship, hunts at night for fish and cephalopods at a depth of 240 m, and this is also not few.

Seals and sea lions have retained a connection with land and, therefore, are less adapted to an aquatic lifestyle than dolphins and whales. But some of the pinnipeds are divers! It is known that the Antarctic Weddell seal can dive to a depth of 610 m. One seal stayed under water for 43 minutes, reaching a depth of 200 m.

For a warm-blooded, air-breathing animal to survive for so long in a world of cold, darkness and crushing pressure is a remarkable achievement. So how does it manage the amount of oxygen that it carries in its lungs and which, at first glance, should not be enough for deep-sea diving? How does it resist not only the direct physical effects of pressure, but also the consequences of rapidly alternating processes of compression and decompression of the body?

Man is surprisingly well adapted for diving, although for him, a terrestrial animal, the underwater world is a much more alien and formidable element than for his younger brothers, who long ago settled in the watery kingdom. Perhaps we can better appreciate the problems that marine mammals have to overcome when diving to great depths if we list the dangers of staying at excessive depths for too long.

For at least 6000-7000 years, people have been raiding the bottom of the sea, extracting pearls, expensive corals, sponges and various types of edible animals. The main character of these raids was a naked diver, he reached the bottom with the help of a stone, and the area of ​​​​his invasion was limited to the coastal zone with depths of 30 meters. Even the Lucayan Indians, pearl divers in the Caribbean, famous as excellent divers to great depths, most likely did not descend (although they are said to be able to hold their breath for 15 minutes). The famous Japanese "ama" - female divers, have been working for over 2000 years at depths of 15 to 24 m. With age, they lose their hearing and their predisposition to pulmonary diseases increases.

Pearl divers from the Pacific Islands descend deeper - up to 42-45 m, but some of them pay for this by falling ill with a strange illness - "taravana", which means "falling in a fit of madness." In different places, attacks of taravana occur differently. They are accompanied by dizziness and vomiting, ending in partial or complete paralysis, and there are also cases of death. Taravana is somehow connected with the breathing pattern. It is not known to the divers of Mangarewa Island, who rest for 12-15 minutes between dives, and the pearl seekers of the Paumotu Islands, who dive to the same depths, but hyperventilate their lungs with frequent and deep breaths for 3-10 minutes between dives, suffer from taravana.

The deepest divers in the world are probably the Greek sponge hunters. They reach depths of about 56 m. (They say that one, now legendary, diver in 1906 retrieved a lost anchor from a depth of 60 m *.) Since ancient times, stories have reached us about the hard work, illnesses and short life of the then Mediterranean divers, but surveys carried out today have shown that their current descendants suffer less from physiological disorders than all other professional divers. On this basis, it is even concluded that over the course of more than a hundred generations, hereditary divers could have developed and consolidated immunity to the effects of deep-sea diving. Whether this is true or not is difficult to say. But when sponge hunters came into the hands of the soft diving suit with helmet, invented in 1837 by August Siebe, and they began to stay at depth longer than their ancestors, half of those who worked in the suit died within a year. Only gradually, acting by trial and error over many years, the Greeks were able to develop diving rules that determined the duration of stay under water, the safe speed of returning to the surface and the permissible frequency of dives. The descendants of those “helmet-heads” and now, by all accounts, can work longer than any of their brothers in the profession. seabed.

* (The depth record for a diver without using any underwater equipment is 73 m. It belongs to submarine crew rescue specialist Robert Croft. But this is precisely a record, and not a working dive with the completion of some task at depth. Having barely reached the 73-meter mark, Croft immediately began to climb. - Approx. auto)

But if, before the invention of the diving suit, the Greek sponge hunters enjoyed a reputation as peaceful and kind-hearted people, then, having started using the “helmet”, they were completely transformed and turned into “a bunch of loud drunkards. In the harbor, all they know is that they get drunk in honor of the fact that returned alive, and are trying to gain courage for a new campaign with the help of alcohol."

* (The Japanese ama is discussed in detail in the book "The Physiology of Immersion and the Japanese Ama" (National Research Council Publication No. 1341, Washington, 1965). The book includes a chapter on the pearl divers of the Tuamotu Islands, written by E. R. Cross. Much of the material on Greek sponge hunters comes from an article by Peter Throckmorton in Man Under the Sea, Chilton Books, 1965.)

From a purely theoretical point of view, it is very difficult to imagine a diver going under water deeper than 30 m. Already at this depth, as emphasized in the textbook for divers of the US Navy, the diver is exposed to a pressure of 4 atmospheres. His lungs, which have a volume of about 6 liters on the surface, are compressed there to 1.5 liters, that is, almost to the so-called residual volume corresponding to complete exhalation. Further diving may cause lung injury due to compression of the chest or pressing of the diaphragm into the chest cavity. In this case, blood and lymph are squeezed into the alveoli and bronchi, where there was residual air under less pressure. The native divers of the Pacific Islands are unlikely to know about this, but may this ignorance serve them to their advantage.

This external “compression” is very dangerous, although resistance to it varies widely. But this is only one of the dangers that a deep-sea diver in a soft suit is exposed to. With increased pressure, nitrogen begins to dissolve in large quantities in the blood. And if a diver stays at depth for a long time, his blood and body tissues have time to become saturated with gas to the limit. With a slow rise to the surface, the dissolved gas has time to be released from the blood and body tissues through the lungs during normal breathing. But if the diver ascends quickly, excess nitrogen will be released in the form of bubbles directly into the vessels and tissues of the body, as happens in a bottle of sparkling water when it is opened. These blisters cause excruciating pain and, in more acute cases, paralysis and death. Although sponge and pearl hunters were the first to encounter this decompression sickness in ancient times, it received its current generally accepted name “caisson sickness” in the 19th century, when its tragic consequences were experienced by workers descending into the caissons, where, under increased pressure, they erected bridges and tunnels under rivers. The only way To avoid decompression sickness is to gradually reduce the pressure so that the nitrogen dissolved in the blood is released without forming bubbles in the vessels and tissues of the body.

Many people believe that a diver who goes underwater without scuba gear or a soft diving suit with a helmet is not at risk of decompression sickness. He spends little time at the bottom, does not inhale compressed air, the remaining air in his lungs is squeezed into the bronchi, from where gas does not enter the blood. All this is true for a single dive, but when a diver goes underwater several times in a row, excess nitrogen gradually accumulates in his blood. And at the end of a series of dives, a person should feel some signs of decompression sickness.

In fact, this is the case, and decompression sickness under various names is well known to professional divers, although they may not understand the essence of the phenomena occurring to them. As an example, I will give a convincing experiment that one medical officer of the Danish Navy performed on himself: after making several dives in a row to a depth of 20 m in a training pool, he felt the symptoms of decompression sickness *. There is only one way to avoid the accumulation of excess nitrogen in the blood: you need to dive at long intervals, during which the normal concentration of nitrogen in the body is completely restored.

* (This experiment was carried out on himself by the Danish officer P. Paulev. He reports his findings in his article, “Decompression sickness after multiple breath-hold dives,” included in Publication No. 1341, referred to in the previous note.)

The Tarawana pearl divers of the Paumotu Islands remain a mystery to us. Unlike decompression sickness, it can manifest itself in the form of sudden and complete paralysis at a time when the diver is at a significant depth. Even more surprising is that Taravana victims do not feel pain. There is no doubt that taravana is a type of decompression sickness, but we have not yet understood why it is so different from the usual form and what exactly causes it.

After the invention of scuba gear, the insidious effects of compressed nitrogen, called nitrogen poisoning, became widely known. However, in a narrow professional circle, this phenomenon has been known for 150 years. The first to experience nitrogen poisoning were divers wearing Siebe's metal helmet. Something strange suddenly began to happen to them. They began to feel an irresistible desire to catch fish with their hands, engage in an intricate dance, and completely forgot about work. There have been cases when a diver with his own hand cut the hoses supplying air to his helmet. For a very long time it was not possible to understand what was going on here, and even now this phenomenon, which Captain Jacques-Yves Cousteau called “the call of the abyss,” has not been fully studied. But under this exciting name it became known to millions of people, and may this fame serve as a warning to careless and imprudent scuba divers.

Nitrogen poisoning awaits a scuba diver or diver in a diving suit with a helmet if he breathes atmospheric air at a depth of more than 30 m. Susceptibility to poisoning is individual, so some divers work calmly at a depth of 60 m, and some do not hear the “call of the abyss” even at a depth of 90 m. Only switching to breathing mixtures that do not contain nitrogen, for example helium-oxygen, can save a person from the dangers of nitrogen poisoning. It is now generally accepted that compressed nitrogen, dissolving in the blood, acts like alcohol or weak anesthetics and narcotics. The higher the pressure, the more pronounced this effect is, more and more reminiscent of the effect of “laughing gas” - nitrous oxide.

Ordinary divers who do not have scuba gear or soft diving suits with helmets are apparently not at risk of nitrogen poisoning. They go to great depths, where there is a danger of such poisoning, very rarely, they do not stay there for long, in addition, the supply of air in their blood and lungs is very limited. But it is possible that if one of them were able to hold their breath for several minutes and dive to a depth of over 60 m, as marine mammals do, such a daredevil would risk hearing the “call of the abyss.”

And finally, about the last danger that awaits a diver on the seabed. The reserves of oxygen dissolved in his blood and body tissues are gradually depleted, and as soon as the concentration of carbon dioxide in the body reaches a certain value, the diver finds himself at the mercy of the unconditioned exhalation-inhalation reflex. Only passion for work or some unexpected event that completely captures his attention can save a person from this reflex; only under these conditions a person does not feel anoxia - a lack of oxygen in the tissues of the body and does not feel an irresistible desire to repeat the breath.

So, anoxia due to a decrease in the concentration of oxygen in body tissues during a long stay at depth, “compression” of the body, decompression sickness in its various manifestations and nitrogen poisoning - this is a short list of phenomena that, in our opinion, marine mammals must encounter, often making deep sea diving. And since cetaceans and seals can withstand long-term dives to significant depths without any damage to themselves, it is clear that over millions of years of life in water, these animals have developed some kind of physiological and anatomical features, protecting against all of the above factors.

But cetaceans and pinnipeds are not the only divers in the animal kingdom. There are many diving birds, and there are semi-aquatic animals such as beavers, otters, water rats and hippopotamuses, which spend a lot of time under water. All of them dive shallowly, but nevertheless their anatomy and physiology have undergone a number of changes that allow them to stay under water for a long time. And many important discoveries concerning the physiology of deep-diving animals were made precisely through the study of small animals that are familiar to you, which often spend long periods at shallow depths.

The pioneer in the field of physiology of immersion in water is the French biologist Paul Baer. Baer was interested in a wide range of issues, and among them was determining the differences between purely terrestrial and diving animals. About a hundred years ago, Baer published a report on his experiments with ducks, beavers and muskrats. Comparing a duck, which spends part of its time under water, with a chicken, which is a purely terrestrial animal, Baer noted that when forcibly immersed in water, the duck becomes quiet for several minutes, and the chicken immediately begins to struggle furiously and dies faster than the duck. Having discovered that a duck's body contains approximately twice as much blood as a chicken's body, Baer concluded that the duck stores twice as much oxygen as the chicken, which explains the ability of ducks to stay underwater for long periods of time. Proving his hypothesis, Baer performed the following experiment: by releasing some of the blood from the duck, he equalized the blood volumes of the duck and chicken and made sure that both birds died under water at the same time.

Later studies showed that the difference in the duration of immersion of different animals significantly exceeds the difference in blood volumes. Consequently, the ability to stay under water for a long time depends not only on blood volume, but also on other features, both anatomical and physiological. In particular, it turned out that when an animal is immersed in water, the frequency of contractions of its heart muscle decreases. This slowing of the heart - bradycardia - leads to a decrease in the supply of oxygen to muscle tissue. Unlike the heart and brain, muscles can work anaerobically for some time (that is, without consuming oxygen) at the expense of their own reserve, which is restored as soon as the animal returns to the surface. And finally, it was found that in diving animals the respiratory center is insensitive to an increase in the concentration of carbon dioxide in the blood. This leads, firstly, to a more complete use of oxygen reserves, and secondly, to inhibition of the exhalation-inhalation reflex.

Physiological mechanisms that regulate the activity of the body under water, as a rule, begin to operate from the moment of immersion (although, for example, for a duck to do this, it is enough to take a pose preceding the dive). All of them belong to unconditioned reflexes and, according to the observations of Lawrence Irving (whom I quoted at the beginning of the chapter), they are not unique to diving animals, although in them these mechanisms are much more developed. Bradycardia when immersed in water occurs, for example, in all terrestrial animals, and in some people it is observed even in cases where they simply immerse their face in water. Interestingly, in fish, bradycardia manifests itself in the reverse order - it occurs when the fish is taken out of the water *.

* (Paul Baer's experiments with ducks and small diving mammals are described in his book Lectures on the Comparative Physiology of Respiration, published in Paris in 1870. More recent work in this area can be read in the following reviews: Lawrence Irving, "The Respiration of Diving Mammals" (see Physiological Reviews, vol. 19, pp. 489-491, 1939); P. F. Scholander "Animals in Aquatic Habitats: Diving Mammals and Birds" (see the collection "Adaptation to the Environment", published by the American Physiological Society, Washington, 1964); H. T. Andersen "Physiological adaptation in diving vertebrates" (see Physiological Reviews, vol. 46, pp. 212-243, 1966).)

Laboratory experiments with small animals have largely clarified the physiological phenomena occurring in the body during immersion, but we still do not understand everything, because we are deprived of the opportunity to directly study these animals in natural conditions. One can only speculate about the physiological characteristics of cetaceans based on the results of studies on the decks of whaling ships. Calculations of cetacean metabolic rates are largely approximate or based on guesswork. There is no consensus even about the depth to which whales dive. Some believe that whales dive very deeply, others, pointing out that we do not know to what depth a whale can dive, nevertheless take the liberty of asserting that no special physiological problems arise during a long dive.

An example of how contradictory opinions are on this matter can be seen in the discussion under the general title “Do whales reach great depths?”, which was raised in the pages of the English magazine “Nature” in 1935. The discussion was started by reader R.B. Gray. Gray argued that a harpooned whale dives straight down and surfaces near the dive site. Consequently, Gray continued, the depth to which the animal dived can be judged by the length of the harpoon line released. Adult bowhead whale In such cases, the tench chooses from 1280 to 1460 m, the bowhead whale, which has not yet reached maturity, from 730 to 1100 m, and the calves - half as much. An adult male bottlenose whale (species not specified) selects 1300 m of tench, females and calves - half as much. Gray believed that these were the depths that whales reached.

The famous English cetologist Dr. F. D. Ommani disagreed with Gray's statements. According to Ommani, the coincidence of the places of immersion and ascent cannot indicate that the wounded whale dives vertically, and, therefore, the length of the etched line does not mean anything. Moreover, Ommani pointed out, the animal’s behavior under these conditions cannot be considered natural. In conclusion, Ommani opined that in normal conditions whales dive no deeper than 360 m. “It is incredible,” he wrote, “that an animal could withstand greater pressure.”

Gray countered with Ommani. He quoted the words of the famous whaler William Scoresby Jr., who emphasized that the length of the harpoon line bays that the whaler keeps at the ready is determined by the depth at the fishing site, and only in very deep places the length of the chosen line depends on the size and strength of the animal being caught. According to Gray, Scoresby's words indicate that the wounded whale is making a vertical dive. Claiming that a wounded whale during a dive reaches only its usual depths, Gray argues as follows: “If a harpooned whale were to go deeper than nature allows it, it would receive serious internal injuries that would deprive it of strength and mobility, and between Moreover, the same Scoresby writes: “Often a whale that surfaced after being wounded looked full of strength.” As an additional argument, Gray cited stories of cases when a whale makes such a deep vertical dive that the line breaks, but the whale does not die, crushed by excessive pressure , but goes free and can even recover from the wound: animals fell into the hands of whalers, in whose bodies the hunters discovered old harpoons *.

* (See Nature, vol. 135, pp. 34-35, 429-430 and 656-657, 1935.)

I don’t know whether Dr. Ommani was convinced by these arguments. In my opinion, the dispute continued for some time.

The Norwegian scientist Per F. Scholander made a great contribution to the study of diving birds and mammals. His first work on this topic, published in 1940, remains unique in its depth and breadth of coverage of the topic. Since Scholander's works have helped us in many ways in our research, I consider it necessary to briefly talk about the results achieved by the Norwegian scientist. According to data received from whalers, and from our own observations of the diving duration of the whales, the most different types Scholander found that the bottlenose whale (2 hours) and the sperm whale (about an hour) are able to stay under water the longest. He noted that before diving, the whale takes several rapid, strong breaths, accompanied by fountains of steam from the blowhole. Having emerged, the whale rests the longer the longer the dive was, and again lets out fountains. Having examined the muscle tissue of the bottlenose whale and sperm whale, Scholander discovered that they contained very a large number of oxygen - almost half of the total oxygen supply in the body. Thus, Scholander partly confirmed the previously expressed guess that during the period of stay under water, the supply of oxygen to muscle tissue is sharply reduced, and the so-called retia mirabilis (“wonderful network”) - a special system of blood vessels developed in cetaceans, supplies blood to the muscles during this time. bypasses the muscles, supplying oxygen only to the heart and brain.

Scholander began researching the question of whether marine mammals suffer from decompression sickness with direct measurements of the depths that the animals reach. As already mentioned, at that time these depths were estimated only tentatively, and the estimates of different scientists differed greatly from each other. Ommani, for example, called the figure 40 m, other scientists - 90 m. It was a known fact that a sperm whale got entangled in a cable at a depth of 275 m. Another fact was also known: a harpooned fin whale dived and broke its cervical vertebrae when it hit the bottom, which was 502 m.

The inventive Scholander constructed a simple depth gauge by filling a glass capillary tube with colored water and sealing it at one end. After the water dried, a deposited layer of paint remained on the inner walls of the tube. When immersed in water, the tube was partially filled from the open end, the paint on the walls of the filled part was dissolved and washed off, and by the ratio of the lengths of the painted and unpainted parts of the tube, it was possible to calculate the depth at which the device had been. The tubes, calibrated in the laboratory, were secured using light harnesses on the bodies of the common moro pig and several seals. A fishing line 180 m long with a float at the end was tied to the harness. The animal was allowed to dive freely several times, and then it was recaptured and the equipment was removed. The greatest diving depth of a harbor porpoise was 20 m, and a six-month-old gray seal reached 76 meters on its first dive.

Scholander repeated these measurements while hunting fin whales, attaching tubes to harpoons and arranging with the whalers not to restrict the movements of wounded animals by tightening the harpoon line (as they usually do). Almost all harpooned animals dived and were still alive when they returned to the surface. The fin whale, which dived to the greatest depth of 365 m, then dragged the whaling ship behind it for half an hour before it was finished off. But one slightly wounded whale, which had gone to a depth of 230 m, surfaced, lay on its side, released several fountains and died. The whalers claimed that such cases had happened more than once. It was impossible to say with certainty that this fin whale died from decompression sickness, but Scholander considered this reason quite probable. As for whether the sperm whale entangled in the cable and the fin whale breaking its vertebrae would have experienced decompression sickness if they had returned to the surface alive (as mentioned earlier), Scholander could not say anything.

Having gained an idea of ​​the depths reached by cetaceans and pinnipeds of various species, Scholander made a comparative study of their lungs and discovered that the greater the depth reached this type animals, the smaller the volume of their lungs in relation to their body size. Consequently, Scholander reasoned, the deeper an animal dives, the less oxygen it carries in its lungs. The discovered pattern was confirmed by the observation that seals exhale before diving, or at the very initial stage of the dive. This means that the diving animal protects itself from excessive dissolution of gases in the blood under pressure by taking with it a minimal amount of air. This is what saves the animal from decompression sickness when quickly returning to the surface. In addition, during a deep-sea dive, the lungs are compressed to a residual volume and the air is squeezed out of them into the thick-walled cartilaginous bronchi, where virtually no gas exchange with the blood occurs. From all this it followed that the greatest danger from the point of view of decompression injury is not deep-sea diving with a quick return to the surface, but a long stay at a relatively shallow depth, where the lungs are not compressed to a residual volume under water pressure. “It may very well be,” wrote Scholander , - that the sperm whale and the bottlenose whale, when diving, strive to cover the first two hundred meters as quickly as possible precisely in order to avoid the danger of decompression injury on their return."

* (P. F. Jålander's work "Experimental studies of the respiratory function of diving mammals and birds" appeared in 1940 in Norwegian (see "Hvalradets Skrifter", No. 22, Oslo).)

All doubts about the depths to which sperm whales could reach of their own free will disappeared in 1957 after the publication of a report on 14 cases in which sperm whales became entangled in underwater cables. In six cases, the cables lay at depths ranging from 900 to 1100 m. The number of these cases is too large to assume that a drowning, agonizing animal was entangled in the cable, although it is not clear exactly how these unfortunate incidents occur. So far, only one more or less plausible explanation has been proposed: the sperm whale, chasing prey at the very bottom, rapidly rushes forward with its mouth wide open, its lower jaw set at a large angle; with its lower jaw caught on the cable from the full stroke, it tumbles (this happens with dolphins caught in a net) and can become hopelessly entangled*.

* (See the article by B. S. Khizn "On whales entangled in deep-sea cables" in the journal "Deep Sea Research", volume 4, pp. 105-115, 1957.)

At the beginning of the chapter, I mentioned that the Weddell seal can hold its breath for 43 minutes and dive 600 m. The lifestyle and immediate habitat of this animal prompted scientists to carefully study the Weddell seal - a large, mobile animal that weighs up to 450 kg. Living in Antarctic waters, it often finds itself in situations where an entire group of animals has to breathe through a single hole in the ice. Dr. J. L. Kooyman used this feature to record the depth and duration of Weddell seal dives. The corresponding sensors were attached to adult seals and the animals were released into the only outlet within a radius of 1.5 km. The seals could only return to the same outlet, where all the equipment was removed from them. Kooyman managed to obtain data not only on the depth and total duration of the dive, but also on the speed of descent and ascent. It turned out that when diving to a depth of 300 m or more, seals descend and return at a higher speed than during shallow dives. Of course, they could have done this, wanting to stay longer at depth, but we should not forget about Scholander's conclusions. Perhaps, when diving to great depths, the Weddell seal instinctively strives to quickly pass the dangerous zone, staying in which threatens it with decompression sickness. And it is quite possible that he slowly returns to the surface after shallow dives for precisely the same reason that a diver who has completed a long work on the seabed is in no hurry to return to the top *.

* (For further details of J. L. Kooyman's work, see his article "An Analysis of the Diving Behavior and Physiology of the Weddell Seal" in Biology of the Antarctic Seas (American Geophysical Union Publication No. 1579, 1967).)

By the time our work began, that is, by 1960, the general picture of the interaction of various biological mechanisms, triggered during deep-sea diving, was very incomplete, and in some ways contradictory.

Sam Houston Ridgway, the first veterinarian for our pets, became very interested in all these questions. We met him when he was an officer and stationed at the air force base in Oxnard, next door to us. The naval units did not have their own veterinarians, and when our dolphins fell ill, we naturally turned to Captain Ridgway’s department for help, especially since in this case we were not hampered by the question of the cost of treatment. Having finished military service, Ridgway joined our station as a civilian, and was entrusted with the care of animal health.

Sam is a man of boundless energy, pervasive curiosity, inventive mind and tenacious spirit. He spent whole days at the station, usually dropping in on weekends to check the condition of the animals and, if necessary, prescribe a course of treatment, and devoted his evenings to writing reports. Within three years he achieved international fame as a specialist in the treatment of marine mammals, and another two years were enough for him to become a famous physiologist.

Sam's first work was devoted to comparing the blood characteristics of three various types dolphins. These were: the white-winged porpoise, discussed in Chapter 3, the Atlantic bottlenose dolphin, which lives in shallow coastal waters (it can reach speeds of up to 37 km/h, but has never been considered the fastest swimmer among cetaceans), and the Pacific white-sided dolphin, or lag, is an animal that lives in the open sea, like the white-winged porpoise, inferior to it in swimming speed and, probably, in diving depth. In other words, in some respects, lags could be considered to occupy an intermediate position between bottlenose dolphins and white-winged dolphins porpoise.

An important part of the work was determining the blood's ability to store oxygen. The amount of oxygen in the body depends on the concentration of red blood cells and total blood volume. No one had tried to measure it before total blood from a living cetacean. When making such measurements on other animals, the researcher simply measured the amount of blood that flowed from the dying animal, obtaining underestimated and inaccurate results.

Sam used a recently developed harmless method based on the introduction of a small dose (radioactive iodine) into the blood of a living organism. 10 minutes after administration (it is assumed that during this time complete blood circulation will occur and iodine will be distributed evenly in it), a small blood sample is taken from the animal and Its radioactivity is determined. The total volume of blood is determined by the degree of iodine concentration. The number of red blood cells is measured by a standard laboratory method.

The results for all three species were strikingly different. The ratio of blood to body weight of the white-winged porpoise was twice that of the Atlantic bottlenose dolphin. The legs took place exactly in the middle. Even greater differences were found in the ability of the blood to be saturated with oxygen. The white-winged porpoise had this ability three times greater than the bottlenose dolphin. The relative weight of the heart of the white-winged porpoise was 1.4 times greater than that of the Atlantic bottlenose dolphin (measurements were carried out on animals that died for one reason or another). The findings were very consistent with what was or was thought to be known about the ecology and behavior of animals of all three species. This explains why white-winged porpoises can swim faster and dive deeper than bottlenose dolphins*.

* (See S. H. Ridgway and D. J. Johnston, "Blood Oxygen Capacity and the Ecology of Three Genera of Dolphins," Science, vol. 151, pp. 456-458, 1966.)

As stated earlier, in the first studies of the physiology of diving, animals were forcibly immersed in water. It is difficult to expect a dolphin or a seal, tied to a board and lowered under the water against its will, to behave in exactly the same way as if it had dived of its own free will. Moreover, during such experiments, animals sometimes died, although they were not forced to do anything that would go beyond their capabilities.

Successfully training dolphins to dive under the command of a trainer on the high seas allowed Sam Ridgway to conduct a unique experiment with Taffy. First, Sam decided to find out how deep Tuffy could dive. And secondly, he decided to analyze the composition of the air exhaled by Taffy in three different situations: a) immediately after surfacing from a great depth, b) after holding the air in the lungs for a time equal to the time of deep-sea diving (provided that the dolphin does not leave from the surface) and c) after the dolphin covers the distance from one diver to another at a depth of 20 m (that is, at shallow depths) in a time equal to the time of a deep-sea dive. At the end of each experiment, Taffy had to dive under an inverted funnel and exhale into it, after which the air samples taken were taken to the laboratory. As you can see, the dolphin had to work very thoroughly.

By this time, Taffy was already diving deeper than 180 m. He learned to swim underwater from one diver to another when called by a buzzer or other acoustic device. Petty Officer Bill Scrons had to teach a dolphin to hold its breath on command for a certain period of time while lying on the surface, and then practice the final spectacular trick - exhaling under an inverted funnel. The dolphin perfectly understood what they wanted from him, and, according to Scrons, mastered the new exhalation system in 10 minutes.

Taffy's place of work was 8 km from the station. Usually he “saddled” the wave diverging from under the propeller of Scrons’ boat, and “rode like a hare” most of the way. Having arrived at the place, Scrons lowered the training device to the prescribed depth, turned on the buzzer, Tuffy dived, pushed the rod with his nose, the sound turned off, the dolphin returned without surfacing, exhaled air under the funnel, and then jumped to the surface for a reward and fresh air.

From the behavior of the dolphin and its echolocation clicks, it was clear that Taffy was continuously monitoring its location from the moment the device was immersed in the water. Perhaps the dolphin could judge the depth at which the device hovered by the intensity of the signal arriving at the surface. Be that as it may, the dolphin always knew to what depth he had to dive, and before diving to 150-180 m, he hyperventilated his lungs, taking 3-4 quick breaths. Since he was hyperventilating even when this deep dive was the first dive of the day, it can be argued that he actually knew where he was going to be sent, and his behavior was not related to the expenditure of energy during the previous dive. When the dolphin had to hold air in its lungs while remaining on the surface, it did not hyperventilate because it could not know in advance how long it would be ordered not to breathe.

In total, Taffy completed 370 deep-sea dives. The total length of the cable, to the end of which the control device was suspended, was 300 m; the dolphin reached this depth and returned back in 3 minutes 45 seconds. During one lesson - 60 minutes - he dived 9 times to a depth of 200-300 m at intervals of 3-5 minutes. While remaining on the surface, Taffy retained air in his Lungs for an average of 4 minutes. The record delay time was 4 minutes 45 seconds *.

* (Peg, who underwent a similar training course, could hold her breath for even 6 minutes. - Approx. auto)

Laboratory analyzes of the gas mixture exhaled by Tuffy fully confirmed Scholander's hypothesis. They showed that greatest number Taffy consumes oxygen during trips from one diver to another at shallow depths. The mixture exhaled by the dolphin after this exercise contained only 2% of the normal oxygen content in normal atmospheric air- a level at which a person would have lost consciousness long ago. Lying on the surface and not breathing, Tuffy consumed less of the oxygen available in his body. But the dolphin consumed the least amount of oxygen during a deep-sea dive. The maximum concentration of carbon dioxide in the exhaled mixture was observed after holding the breath on the surface, and the minimum - after a deep-sea dive, although it required a much greater expenditure of effort from the animal.

The data obtained suggest that when diving deeper than 90 m, the oxygen stored in the dolphin’s lungs diffuses into the blood very slowly. The same probably happens with nitrogen. This means that Scholander is right: decompression injury threatened Taffy not during a rapid ascent from great depths, but after long stay at a relatively shallow depth.

Divers observed the effect of pressure on Taffy’s chest even at a depth of 20 meters. To see what a dolphin looks like at a depth of 300 m, Sam attached an underwater camera to the control device, and Tuffy took a photo of himself at the moment when the buzzer turned off. The picture clearly shows that the dolphin's chest has the ability to significantly decrease in volume without any damage to the animal.

As often happens, the experiments performed did not so much answer questions as raise new ones. It is unclear how Tuffy could be active with such low levels of oxygen supply as Sam recorded. According to Ridgway's calculations, the stored oxygen was barely enough to maintain cardiac activity. But how did the brain cope, the action of which in an oxygen-free mode is impossible to imagine? And yet there were no signs of oxygen deficiency in Taffy's behavior*.

* (Experiments with Taffy are described in the article "Breathing and deep-sea diving of the bottlenose dolphin" by S. H. Ridgway, B. L. Scrons and John Kanwisher (see Science magazine, vol. 166, pp. 1651-1654, 1969).)

We were able to train a sea lion to dive on command to a depth of 230 m, and a pilot whale to dive to 500 m. As with Tuffy, we cannot say that this is their limit. Moreover, we witnessed a pilot whale dive to 610 m on its own initiative.

Thus, through the work of our specialists, the stock of knowledge about how deep marine mammals are capable of diving and how long they can stay under water has been replenished. And now we have the right to say that trained cetaceans and pinnipeds can deliver scientific information to humans from 500-meter depths in the open sea. Moreover, such information that cannot be obtained by any of the methods known to us.

Mammals that live in water do not have a larger lung volume-to-body size ratio than mammals that live on land, but they can submerge for long periods of time while holding their breath because they have evolved alternative mechanisms to increase the amount of oxygen they inhale. This article examines some of these mechanisms.

Unlike their land-diving counterparts, seals, sea lions and whales dive while holding their breath for practical reasons - for example, to find food or escape from predators. As is the case with land-dwelling animals, these dives are accompanied by physiological changes that require certain adaptations.

The extent of this adaptation is greater than even that observed in the most accomplished human freedivers. This ability for increased adaptation provides a partial explanation for the depth and duration of dives performed by such mammals. For example, the current record for the no-limit discipline of 163 meters is a relatively shallow depth compared to the depths to which bottlenose swimmers descend. The use of means that record the time and depth of the dive, as well as acoustic transceivers, made it possible to track the dive of these whales to depths of up to 1,450 meters. In comparison, the northern elephant seal dives to depths of up to 1,500 meters, although it should be noted that diving to such depths is not the norm for these animals.

Perhaps the most effective physiological "equipment" is possessed by the New Zealand sea lion, a mammal capable of making longer dives than any other species, typically descending to a depth of 120 meters (the greatest depth recorded was 474 meters) and easily remaining at this depth for five minutes. Although similar depths and durations of dives are available to other marine mammals, what sets these animals apart from others is the manner in which they dive, as they dive underwater almost continuously. Of interest to freedivers is the fact that almost half of the dives performed by this sea lion exceed its theoretical aerobic diving threshold (ATD, see below).

Calculation of aerobic diving threshold

In theory, if a freediver starts a dive with full lung volume (FLC), the maximum theoretical depth can be calculated by the ratio of FLC to residual lung volume (RLV). Based on these calculations, it is possible to predict the maximum "theoretical depth" or "stopping point" that can be reached by Pipin Ferreras, a diver whose FLOOR is 9.6 L and TOL is 2.2 L. Applying the Boyle-Mariotte law, it can be established that the safe compression threshold for Ferreras is about 4.4 atmospheres (at absolute pressure), which corresponds to a depth of 34 meters. Fortunately, in sport freediving, athletes pay little attention to the laws of physics, so Ferreras dived 128 meters deeper than his theoretical maximum depth. Clearly, there are diving mechanisms that allow freedivers and seals to circumvent these laws.

For freedivers who want to calculate their theoretical depth threshold, there is the following formula (for practical use only).

Assessment of residual volume (RV) of the lungs depending on age, height and body weight.

In freediving, TCO affects the depth a freediver can reach without experiencing chest compression problems. Usually the ratio of LPO to TOL on the surface determines maximum depth dive, during which the athlete will not experience compression of the chest. One way to set your OOL is to perform the following calculations.

Equations for calculating OOL

Variables: age (years), height (cm), weight (kg).
Normal weight - men:
TOL (l) = (0.022 x Age) + (0.0198 x Height) – (0.015 x Weight) – 1.54
Normal weight – women:
GOL (l) = (0.007 x Age) + (0.0268 x Height) – 3.42

The mechanisms by which "animal divers" resolve the contradiction between the energy demands of a dive and the conservation of limited oxygen supplies are similar to those encountered by land-based freedivers and are not fully understood. However, our marine counterparts certainly have some physiological advantages at their disposal.

For example, a seal's maximum dive time is not determined solely by its ability to retain oxygen, since seals can operate in an anaerobic mode. However, aerobic metabolism is preferable to anaerobic metabolism because it is much more efficient. Reducing their metabolic rate allows seals to increase the amount of time they maintain aerobic respiration during a dive, as this allows them to use up their oxygen reserves more economically. In addition, through selective tissue perfusion, seals are able to increase the duration of their oxygen supply. The moment at which a seal or other diving animal needs to surface and inhale oxygen or switch to anaerobic respiration is called APN. The level of lactic acid salts in the blood begins to increase above resting values ​​after reaching APN and leads to a burning sensation in the muscles.

So how do seals function anaerobically? Unlike human tissues, seal tissues tolerate three factors of asphyxia much more easily: lack of oxygen, high level carbon dioxide and low pH. Lack of oxygen is caused by oxygen consumption during aerobic respiration, carbon dioxide is a waste product from muscles, and low pH is the result of lactic acid released during anaerobic respiration. The ability to easily tolerate these three factors allows the seal to operate in an anaerobic mode after depleting its oxygen supply.

Prolonged dives usually force seals to exceed the ALP and resort to anaerobic respiration. This was experimentally established by taking blood: an increase in the level of lactic acid salts in the blood indicated that the seal was using anaerobic respiration. Seals use different ways diving to get rid of residual lactic acid that accumulates during anaerobic diving. For example, dive recovery time for Weddell seals varies depending on the length of time spent underwater. After several long dives (about 20 minutes each), these seals perform a series of short aerobic dives, which gradually remove accumulated lactic acid salts from the blood.

Another strategy used by seals, sea lions and whales to store oxygen is to achieve energetic efficiency. As might be expected, the depth of the dive and therefore the distance traveled influence the amount of time available for gliding, which is the primary method of oxygen conservation used by marine mammals. The amount of time spent gliding smoothly during a dive increases significantly and non-linearly with dive depth and translates into significant energy savings in terms of oxygen use.

Another mechanism used by seals is how they store oxygen. Seals do not use their lungs to store oxygen. As you can see in the graph, during a dive there is significantly less oxygen in a seal's lungs than in a human's lungs. When diving, the seal cannot store oxygen in its lungs due to the serious risk of decompression sickness upon surfacing.

Graph: Location of oxygen reserves

Purple is a seal, lilac is a person.

So how does a seal store oxygen? The answer lies in the blood and tissues.

Seal blood has a better oxygen-carrying capacity than human blood, partly due to seals' larger blood volume and partly due to their higher hematocrit (hemoglobin concentration). Because there is more blood in a seal's body, it has more red blood cells (erythrocytes). More red blood cells lead to higher levels of hemoglobin, the blood pigment found in red blood cells that carries oxygen. However, seal red blood cells have a lower water content than red blood cells land mammals Therefore, even at the cellular level, this animal is designed to store more oxygen - this explains its higher hematocrit. Of course, the content of red blood cells in the blood is limited, because, as we know, if there are too many of them, the blood becomes too thick for normal heart function. However, marine mammals get around this limitation by resorting to additional methods of storing oxygen for later use.

One of these methods is the use of myoglobin, that is, a compound found in muscles that binds oxygen. In fact, myoglobin is so highly concentrated in seal muscle that under a microscope it appears almost black! Humans also have myoglobin, but unfortunately for freedivers, its oxygen storage capacity is much less than that of seals.

Type / Myoglobin (g/100 g)
Northern fur seal - 3.5
Sperm whale - 5.0
Weddell seal - 5.4
Striped seal - 8.1

Among other things, marine mammals are able to store oxygen in body tissues that humans cannot, giving them the ability to store more oxygen. This is especially true for the spleen. The mechanism for storing oxygen in the spleen is similar to that used by humans, but the oxygen capacity of the spleen of marine mammals is much greater than that of humans.

FINVAL

length up to 24 m

weight up to 80 t

What does it look like

The fin whale is the second longest whale after the blue whale. The body of the fin whale is very slender and elongated. The height of the fountain is up to 8 meters in height. The back is dark gray or dark brown, and the belly and underside of the fins are light. Fin whales can be clearly identified by different colors lower jaw - the right side is white, and the left is dark. This coloration also extends to whalebone. Its dorsal fin is quite low, located closer to the tail. There is often a white spot on the dorsal fin.

Number and habitats

In Russian waters, fin whales can be found in all Far Eastern seas. During the winter months they migrate to warmer waters.

The number of fin whales before whaling in the North Pacific Ocean was approximately 45 thousand animals, but it was thoroughly undermined by the fishery. Currently, it is believed that up to 16 thousand fin whales live in the North Pacific Ocean.

How long does he live?

The fin whale lives more than 90 years.

Animal behavior

It lives far from the coast, but can go to deep coastal waters for food. Fin whales most often stay alone, less often not in large groups. They stay more united when feeding on schooling fish. Fin whales move faster and can dive deeper than most other large whales. Its normal speed is 15 km/h, and its diving depth is up to 500 meters.

What does it eat and how does it hunt?

It feeds on small schooling fish, krill, squid and plankton. When feeding, it captures accumulations of food along with water into a huge oral sac, inflating it like a ball. Then it filters the water through the whisker plates. The densely filled stomach of the fin whale contains up to 1000 kg of food. Feeding whales can move sideways with their mouths open, roll over on their sides or belly up, and make sudden, jerky movements.

Offspring

The female gives birth to her first calf at the age of 6-12 years. A cub is born once every 2-3 years, usually in winter. Pregnancy lasts about a year. The female feeds the baby whale with milk for about six months.

The main threats to the extinction of these whales are general ocean pollution, entanglement in fishing nets and collisions with ships. High-speed vessels are especially dangerous.

How they study

Currently, there is almost no study of the fin whale in the Pacific Ocean. Most current research on this species is conducted in the Atlantic Ocean and Mediterranean Sea.

Minke whale (MINKE)

length up to 8 m 50 cm

weight up to 10 t

What does it look like

The minke whale is one of the smallest baleen whales. The whale is dark gray in color with a white belly. Minke whales have a wide white stripe on their pectoral fins. This sets it apart from other whales.

A whale jumps out of the water quite rarely. The fountain shoots small and never shows its tail when diving. Most often, only the dorsal fin, which is shaped like a sickle, is visible from the water. Minke whales are fast-moving and easy to lose sight of.

Number and habitats

Minke whales are found in all Far Eastern seas. In winter it usually swims to warmer waters. Its population in the Pacific Ocean is approximately 9 thousand animals.

How long does he live?

The minke whale lives about 50 years.

Animal behavior

Minke whales often stay close to the shore in bays and bays. They usually live alone, less often in pairs. In places where food accumulates, they can gather in groups. Minke whales usually dive for 5 - 8 minutes, and can stay under water for up to 20 minutes.

What does it eat and how does it hunt?

Minke whales feed on small schooling fish or planktonic crustaceans (small crustaceans). They usually feed at the surface of the water: making a swift dash into the center of a school of fish or a cluster of plankton, it sucks in the prey along with the water, and then drains the water with the help of a whalebone.

Offspring

The female gives birth to one calf every year or every other year. Pregnancy lasts 10 - 11 months. The cubs are fed milk for about six months. The size of newborn whales is about 3 meters and weighs 400 kg.

Enemies in nature and threats from humans

Increase in the scale of whaling. General ocean pollution. Depletion of food resources on which the whale feeds.

How they study

The Pacific Ocean is practically unexplored.

GORBACH

length up to 18 m

weight up to 30 t

What does it look like

The most distinctive features are the whale's pectoral fins. They are very long, often visible even through water. The leading edge of the pectoral fins is covered with skin bumps. The color of the underside of the pectoral fins is most often white, and the color of the tail can range from completely white to black. The elongated head is covered with several rows of rounded cones. Each cone contains a vibrissae, a sensitive hair. On the head, pectoral and caudal fins there are often growths from the shells of barnacles. Whalebone plates up to 1 m high.

Number and habitats

The number of humpback whales in the North Pacific Ocean is estimated at approximately 16 thousand individuals.

Humpback whales often stay in relatively shallow waters, but during migration they can also be found far from the coast. Humpback whales breed in the southern regions, and feed (feed) in the waters of Chukotka, Kamchatka and the Commander Islands, off the coast of Alaska. In the Sea of ​​Okhotsk, these whales are quite rare, although as the population of the herd recovers, they are becoming more common.

How long does he live?

The humpback fish lives for more than 50 years.

Animal behavior

Humpback whales usually live alone or in groups of up to 15 animals, but can gather in large groups in places where food is abundant. Humpback whales are slow-moving, but on the surface of the water they often behave actively: they stick out their heads and pectoral fins, jump out of the water, and beat their tails. They usually dive for 3-15 minutes, but sometimes stay under water for up to 40 minutes, diving to a depth of up to 150 m. Humpback whales, more often than other minke whales, jump out of the water entirely, often rotating around their axis. Tourists love to watch these whales for their spectacular acrobatic behavior. Males in breeding areas are also characterized by long "songs".

What does it eat and how does it hunt?

Commonly targeted schooling fish include herring, cod, mackerel, capelin and sardines. To gather fish into a tighter school, humpback whales swim in circles and then suddenly emerge vertically with their mouths open to capture as much prey as possible. Humpbacks can also school fish using what is called a "bubble net", swimming around the school and releasing air bubbles. In Russian waters, humpback whales often feed on small planktonic crustaceans, accompanied by large concentrations of birds.

Offspring

Humpback whales become adults at the age of 5-11 years. Once every 2-3 years, the female gives birth to a single cub 4-5 m long. Usually the cubs are born in January-February. Pregnancy lasts 11-12 months, the duration of feeding the baby is 6-12 months. In breeding areas they can form groups that consist of a female and one or more males. In this case, one male follows the female, trying to stop the attempts of rivals to approach her.

The threat to humpback whales comes from general ocean pollution, entanglement in fishing nets, and disturbance of animals in feeding and breeding areas due to excessive activity of whale watching tourists.

How they study

Since the cessation of whaling, no studies of humpback whales have been conducted in Russian waters. In 2004-2006, a large-scale international project for the study of humpback whales in the North Pacific Ocean - photographs of humpback whales were carried out, a photo catalog was created, and skin samples were collected for genetic research.

BOWLAND WHALE

length up to 19 m 80 cm

weight up to 100 t

listed in the Red Book of the IUCN and Russia

What does it look like

The bowhead whale has a massive, thick body with a wide back. The rest of the whales are inferior to him in fatness. For example, a sperm whale with the same length weighs only 50 tons.

The bowhead whale's mouth line is arched. There is no dorsal fin. The baleen plates are narrow, dark gray or black, up to 4 m long. This is the maximum length among baleen whales.

Number and habitats

The world population of bowhead whales is estimated at about 25 thousand individuals. There are about 300 whales in the population living in the Sea of ​​Okhotsk.

How long does he live?

The lifespan of bowhead whales can exceed 100 years.

One day, fragments of a 19th century whaling shell were found in the body of a bowhead whale. This kut died when he was approximately 115-130 years old. This age, according to scientists, is very rare. But experts believe that some whales can live up to 200 years.

Animal behavior

Bowhead whales live alone or in small groups. In places where food accumulates, groups of up to 60 or more animals can form.

Slow swimmers, but on the surface of the water they can be quite active: they jump out of the water, hit the surface with their fins and tail; ships are often allowed to come close. When diving, the tail fin is often shown. While feeding, they often surface in the same place where they dived. When diving, they usually stay under water for less than 20 minutes, although they can dive for 40 minutes and reach a depth of 200 m. They can swim under the ice and make holes in it for breathing, breaking ice more than 1 m thick.

What does it eat and how does it hunt?

Bowhead whales feed on small planktonic crustaceans. They can feed near the shore at shallow depths.

Offspring

Bowhead whales become adults at the age of 20-25 years. Pregnancy lasts 12-14 months. The female gives birth to one cub every 3-4 years. The calves are born 4-5 meters long in April-June. Bowhead whales have very strong bonds between the female and the calf. Females nurse their young for about 12 months.

Enemies in nature and threats from humans

The threat to bowhead whales is posed by general ocean pollution, global warming, which causes a decrease in ice area, and changes in the food supply. Concerns associated with increased human activity in the coastal areas of the Arctic seas are also increasing.

How they study

Due to the fact that the bowhead whale is an object of indigenous whaling, it is quite well studied. Research on this species is carried out in Alaska: they study nutrition, migration, growth and development, and the degree of pollution of the whales’ body. Satellite tagging has revealed that these whales migrate widely between Russia and the United States.

JAPANESE SMOOTH WHALE

length up to 18 m 50 cm

weight up to 80 t

listed in the Red Book of Russia

What does it look like

The body of the Japanese right whale is massive and thick, without a dorsal fin. On both sides of the upper jaw there are black whalebone plates. The body color of the whale is black or dark brown, some with white spots on the chin and belly. The large head of a whale is covered with large light growths. These growths are of natural origin and appear already in the womb. The location of these growths varies among whales, which helps scientists distinguish the animals from each other. Males usually have more growths than females.

Number and habitats

The Japanese right whale is found in the waters of the Far East from the Sea of ​​Japan to the Bering Sea. This is one of the rarest whales. Presumably, only 200 individuals live in the Far Eastern seas of Russia. To date Japanese whale is in danger of extinction. This is due to the fact that Japanese whales were the basis of whaling in the 19th and early 20th centuries. From one killed whale, whalers received 15–18 tons of fat, because the skin layer of fat on the back of a whale reaches a thickness of 36 cm, and on the sides - 20–25 cm. And especially many Japanese whales were caught in the Sea of ​​Okhotsk.

How long does he live?

The Japanese right whale lives more than 70 years.

Animal behavior

Japanese whales usually live alone and are rarely seen in pairs. During the breeding season, whales gather in groups. They are not shy, quite curious and often allow observers to come close. The whale moves slowly and calmly. It is often active, jumping out of the water, splashing the water with its pectoral fins. It usually spends 10-20 minutes underwater, although it can stay there for up to 50 minutes and dive to a depth of more than 180 meters.

What does it eat and how does it hunt?

The Japanese right whale feeds on small planktonic crustaceans on the surface of the water. Through the whalebone, the whale expresses water, leaving barbels on the back side, which it licks with its tongue.

Offspring

The female gives birth to her first calf at the age of 10 years. The female gives birth once every 2-4 years. Pregnancy lasts 12-13 months. Births occur in December-March in wintering areas, usually in coastal waters. For the first year of life, the cub feeds on mother's milk.

Enemies in nature and threats from humans

The Japanese right whale suffers most from fishing nets in which it gets entangled and from general ocean pollution. Animals also die from collisions with ships.

How they study

Currently, no work is being done to study the Japanese right whale in Russia. Only incidental information about random encounters with them is collected.

GRAY WHALE

length up to 15 m

weight up to 35 t

listed in the Red Book of Russia and the IUCN (Okhotsk-Korean population)

What does it look like

Number and habitats

Gray whales are found in the coastal zone of the North Pacific Ocean and in the Chukchi Sea. There are only two groups of gray whales. One feeding group goes to the shores of Chukotka; their number is 21 thousand animals. The second group feeds in the Sea of ​​Okhotsk off the coast of Sakhalin; there are less than 200 gray whales in this group. The second group of whales is called the Okhotsk-Korean population and is protected by the international Red Book.

How long does he live?

The gray whale lives more than 50 years.

Animal behavior

The gray whale leads a coastal lifestyle and is often found several tens of meters from the shore. Gray whales are active and mobile. They often show their head out of the water and jump out of the water almost vertically. They are not afraid of ships and boats. They live alone and in small groups of 2-3 animals, but in feeding areas they can form aggregations of several hundred animals. They can stay underwater for up to 25 minutes and dive to a depth of 170 meters.

What does it eat and how does it hunt?

The gray whale feeds on benthos - small invertebrate bottom crustaceans. It feeds at shallow depths, collecting food from the bottom. The whale turns on its right side, plows the bottom with its muzzle, scoops up benthic organisms along with water, silt and pebbles and strains the prey through the whalebone. As a result of these feeding habits, the right side of the whale’s muzzle is covered with scars and abrasions. In mature whales, the right eye sometimes loses vision. Less common are left-handed whales, which feed on their left side. An adult gray whale eats more than 500 kilograms of food per day.

Offspring

The female gives birth to her first calf at about 8 years of age. Then the cubs appear every 2-3 years. Pregnancy in gray whales lasts about a year. The mother feeds the baby milk for about 8 months.

Enemies in nature and threats from humans

Gray whales are adversely affected by general ocean pollution. They can become entangled in fishing nets. Oil production in the northeast of Sakhalin is carried out directly in the main summer feeding areas of gray whales, which can interfere with the feeding of the whales and the growth of the animals' numbers.

How they study

Gray whale research in Russia was carried out in Chukotka, as well as off the coast of Sakhalin Island. Scientists distinguish gray whales from each other by the shape of their humps and patterns on their bodies, assign them names and monitor their movements. Also, these differences between them help to better understand the number of animals. Scientists have compiled a photo catalog of gray whales and given them names.

SPERM WHALE

length up to 20 m

weight up to 50 t

What does it look like

The largest of the toothed whales. The sperm whale has a rectangular head. Most of the volume of the head is filled with fat, which is called spermaceti. It helps the sperm whale hunt squid at great depths. The whale's lower jaw is long and narrow with large teeth. The blowhole is shifted to the left side of the head, so the fountain is directed to the left. Sperm whale skin dark color, wrinkled and folded, which is why among English-speaking whalers in the past its slang name was “prune”. The Sperm Whale does not have a dorsal fin, but does have a tall triangular crest.

Number and habitats

The sperm whale is distributed throughout the world's oceans with the exception of the polar regions. The number of sperm whales in Russian waters is unknown.

Males prefer to feed in cold waters, moving further north with age. In this regard, predominantly males are found in Russian waters. In the Far East, but especially often, males are found along the Kuril Islands and near the Commander Islands. Groups of females may approach the Kuril Islands in summer.

How long does he live?

The sperm whale lives more than 60 years.

Animal behavior

Females with cubs stay in warm waters in groups of 10-50 animals. With age, the males gradually separate and gather in groups of young males, which begin to migrate to the north. Large adult males usually live alone or in small groups. They go to the polar regions to feed, and from time to time return to the tropics to breed.

What does it eat and how does it hunt?

Sperm whales feed on large deep sea squid, for which they can dive to a depth of 3 kilometers, remaining under water for more than 1 hour. In search of prey, the whale makes very deep dives. The sperm whale searches for prey using echolocation, in which important role spermaceti plays. Spermaceti also improves the whale's buoyancy when diving. Emerging to the surface, sperm whales rest for some time, remaining in one place and releasing fountains.

Offspring

The female gives birth to her first calf at the age of 7-13 years. Females give birth once every 3-6 years in warm waters. Pregnancy lasts up to 17 months. Usually one baby whale is born, 3-4 m long and weighing about a ton. Females can feed their cubs milk for up to three and a half years.

Enemies in nature and threats from humans

In nature, the sperm whale has practically no enemies, with the possible exception of killer whales, which pose a significant threat to females and young animals.

Plastic waste also poses a threat, especially plastic bags, which these animals can ingest in large quantities and die as a result.

There have been cases of sperm whales dying from entanglement in fishing nets or as a result of collisions with ships.

How they study

This species has been quite well studied; research into the biology and behavior of sperm whales is being carried out in different parts of the world. In Russia, in recent years, work has begun on photo-identification of sperm whales in the waters of the Commander Islands and on studying sperm whale migrations using satellite tagging.

Dwarf sperm whale

length up to 3 m 40 cm

weight up to 400 kg

What does it look like

The pygmy sperm whale is a toothed whale. Unlike the real sperm whale, its body shape is similar to that of a dolphin. He also has a small rounded head. Behind the eyes there is a pattern resembling gills. That's why they called it false gills. The color is bluish-gray on the back, light gray on the sides, white or pinkish on the belly.

Number and habitats

Rare little-studied species, abundance unknown. Recorded only on the southernmost border of the Far East: in the south of Primorye and in the area of ​​the southern Kuril Islands.

How long does he live?

It is unknown how long an animal can live. The oldest age that scientists have determined is 22 years.

Animal behavior

They usually live alone or in groups of 6-7 individuals of different ages and sexes. They spend a significant amount of time lying motionless on the surface of the water. When disturbed or frightened, they can expel reddish-brown intestinal contents, which may help them hide from predators such as large sharks and killer whales. Occasionally they jump out of the water.

What does it eat and how does it hunt?

Offspring

The female gives birth to her first calf at the age of 4-5 years. Pregnancy lasts up to 11 months. Females can feed their cubs milk for up to a year.

Enemies in nature and threats from humans

Often dies when caught in nets. Plastic waste also poses a threat, especially plastic bags, which sperm whales can swallow in large quantities and die as a result. The pygmy sperm whale suffers from exposure to loud noise (military sonar, seismic surveys).

How they study

Practically not studied. Observations at sea are rare, and most work involves the study of dead animals washed ashore.

Encounters with the dwarf sperm whale are very rare, so any information about them is important to scientists. If you encounter these animals, even dead ones on the shore, you should call the marine animal assistance group Friends of the Ocean.

NORTH PLAVUN

length up to 12 m 80 cm

weight up to 15 t

What does it look like

The northern swimmer has a very elongated body with many light scars and scratches on the skin. To others hallmark This whale has an elongated "beak". In adult animals, small teeth protrude forward at the end of the lower jaw. The northern swimmer is the second largest toothed whale after the sperm whale.

Number and habitats

Northern swimmers live in deep, open waters. In Russia they are found in deep-water areas of the seas of the Far East. The exact numbers in Russian waters are unknown, but the northern swimmer is not common.

How long does he live?

The northern swimmer lives approximately 80 years.

Animal behavior

They are kept in groups of 2-9 animals. Quite often they jump low out of the water. They stay under water for 10-30 minutes, sometimes more than an hour. They often dive to depths of more than 1 km, and sometimes even up to 3 km. After diving, they rest on the surface for several minutes. The sounds made by this whale resemble the roar of a bull.

What does it eat and how does it hunt?

Northern swimmers usually feed on deep-sea fish and cephalopods - squid and octopus. In search of prey, the swimmer makes very deep dives.

Offspring

Males become adults at 6-11 years, and females at 10-15 years. The female gives birth to one cub every 3 years or less. Newborn cubs are 3-4 m long.

Enemies in nature and threats from humans

Swimmers can be attacked by killer whales, and fishing nets and ocean pollution are also a major threat. Northern swimmers can die as a result of exposure to loud sounds, for example during military exercises.

How they study

In Russian waters it has practically not been studied. Abroad (for example, in Japan), the study of floating fish is associated with its fishing.

KUVIER'S BEAKED SNAIL

length up to 7 m

weight up to 3 t

listed in the Red Book of Russia

What does it look like

Beaked whales have a light, large body. Adult males are often covered with long, light scratches from the teeth of other males. Adult males have only two teeth at the end of the lower jaw, visible even with closed mouth. In females and juveniles, the teeth are hidden inside the gums.

Number and habitats

The number of beaked whales is unknown. A rare species, but in some areas it is found quite often, for example, on the Commander Islands.

How long does he live?

The beaked whale lives approximately 60 years.

Animal behavior

Beaked whales live alone or in groups of more than 3 animals. Solitary animals are most often old males. Usually beaked whales avoid ships, but sometimes they can swim up out of curiosity.

What does it eat and how does it hunt?

They feed at depth mainly on squid, less often on fish and crabs. They can remain underwater for 20-40 minutes.

Offspring

Scientists know very little about the birth and feeding of young.

Enemies in nature and threats from humans

They often die when caught in fishing nets. There are known cases of massive beaching of beaked whales after military exercises using loud underwater sounds (military sonars).

How they study

In Russian waters it has practically not been studied. Research is being carried out abroad.

BELUHA

length up to 6 m

weight up to 1.5 t

What does it look like

A striking feature of beluga whales is their white color bodies. But beluga whales are born gray, and only by the age of 5-7 years do they become pure white. Shortly before molting, a yellowish tint may appear on the body of adult animals. Beluga whales have a dense body without a dorsal fin. Unlike most cetaceans, belugas can bend their necks and move their heads.

Number and habitats

Beluga whales inhabit cold Arctic waters and also live in the Sea of ​​Okhotsk. With the arrival of spring, they begin to move closer to the coast - to shallow bays and river mouths. They spend the entire summer near the coast because of the abundance of food and warmer water. Beluga whales are attached to the same places, visiting them in the summer from year to year. IN winter time As a rule, they stick to the edges of ice fields, but sometimes they penetrate far into the glaciation zone, where winds and currents support cracks in the ice. Presumably, the total number of beluga whales is about 150 thousand animals, but they are divided into a large number of groups living in different areas, so there is no exact data.

How long does he live?

The beluga whale lives more than 50 years.

Animal behavior

Beluga whales usually live in groups of 5-10 individuals. Groups of beluga whales often consist of animals of different ages and sexes and are related to each other. In places where food accumulates, beluga whales gather in large herds of up to a thousand animals. They make many different sounds: whistles, piercing screams, roars, audible even from under the water. Beluga whales often raise their heads above the surface of the water, stick out vertically from the water and beat their tails. Beluga whales can dive to a depth of 800-1000 meters and remain underwater for up to 25 minutes.

What does it eat and how does it hunt?

Beluga whales usually feed at the bottom and often organize collective hunts. The prey is various types of fish, as well as a variety of worms, crustaceans and sometimes mollusks. Beluga whales can both suck in water and release it in a stream to reach prey hidden in a shelter.

Offspring

A female beluga whale gives birth to her first calf at 6-9 years of age. From now on, she gives birth approximately once every 3 years. Pregnancy lasts 12-14 months. The cubs remain with their mother until they are 2 years old.

Enemies in nature and threats from humans

The natural enemies of beluga whales are polar bears. Also dangerous enemy considered to be a killer whale. Currently, there is no active hunting for beluga whales, but they are being caught for dolphinariums. In captivity, animals often get sick and die. A great danger for belugas is human development of the coastal zone and water pollution with waste and toxic chemicals.

How to study:

The beluga whale is one of the few cetacean species that is actively studied in Russia. Work on the study of this species is carried out in different areas. Satellite tagging of beluga whales is being carried out in the Sea of ​​Okhotsk. These tags provide information about the movement of animals.

ORCA

length up to 9 m 40 cm

weight up to 5.6 t

What does it look like

Killer whales are large toothed dolphins. Because of their size, killer whales are mistakenly called whales. The body of killer whales is dense with large dorsal and pectoral fins. In males, the dorsal fin can reach a height of up to 2 meters. The killer whale has a bright black and white coloration. Behind the dorsal fin there is a light gray saddle-shaped spot. The shape and size of the saddle-shaped spot are individual for all killer whales and are never repeated, like human fingerprints.

Number and habitats

Killer whales live in almost all seas and oceans, preferring colder areas. They can be found both near the shore and in the open sea. In the Far East, killer whales are found in all seas, including in the Kuril Islands and off the coast of Sakhalin. The number of killer whales in Russian waters is unknown. According to various estimates, for example, about 500-700 killer whales live off the eastern coast of Kamchatka.

How long does he live?

Killer whales live up to 90 years.

Animal behavior

Killer whales live in small groups consisting of maternal family members. The oldest female, the “grandmother,” is considered to be the head of the family. Each family of killer whales has its own language. Thanks to this language, killer whales can recognize relatives and distinguish strangers. Killer whales are divided among themselves into piscivores and carnivores. Families of fish-eating killer whales are large; children of both sexes remain in the pod for their entire lives. Carnivorous killer whales have small families, consisting of 3-5 animals; some animals leave their native group and create their own families. Fish-eating and carnivorous killer whales do not communicate with each other in nature, even if they find themselves in the same water area. Fish-eating killer whales are more often found in open waters. Carnivorous killer whales spend most of their time in the coastal zone.

What does it eat and how does it hunt?

Fish-eating killer whales feed only on fish, sometimes showing preference for a particular species of fish. When a school of fish is discovered, the killer whale presses it to the shore or drives it into a dense ball at the surface of the water, then, in turn, dives into its middle and kills the fish with blows of its tail. Carnivorous killer whales feed on marine mammals: fur seals, seals and even the calves of large whales. Killer whales have a variety of hunting methods. For example, when hunting for seals or penguins on an ice floe, several killer whales simultaneously hit the water with their tails, creating a high wave that washes the prey out to sea.

Offspring

The female gives birth to her first calf at 15 years of age. Cubs then appear every 3-8 years. Pregnancy lasts 15-18 months. Cubs begin to try solid food at about one year of age, but sometimes continue to feed on mother's milk until they are 2 years old.

Enemies in nature and threats from humans

For killer whales, general ocean pollution, depletion of the food supply, and entanglement in fishing nets are detrimental. Carnivorous killer whales are captured for aquariums. Orcas have a hard time being separated from family members, often get sick and die in captivity.

How they study

In Russia, research on killer whales is carried out only in the Far East, mainly in Kamchatka, the Commander and Kuril Islands.

PACIFIC WHITE-SIDED DOLPHIN

length up to 2 m 30 cm

weight up to 155 kg

SQUIRT DOLPHIN

length up to 2 m 10 cm

weight up to 110 kg

What does it look like

Dolphins have a very strong body. Dolphins have a very distinctive nose, by which they are easily recognized. A dolphin's nose is also called its beak or rostrum.

Number and habitats

The exact number in Russian waters is unknown. They stay mostly away from the coast, but often enter bays and lagoons. In the northwestern part of the Pacific Ocean inhabits the waters of Japan, Sea of ​​Okhotsk and the Kuril ridge.

How long does he live?

The lifespan of these dolphins is about 35-40 years.

Animal behavior

They usually live in groups of several dozen animals. They often gather in large herds of several hundred dolphins.

One of the fastest dolphins. Active playful animals, often jumping out of the water and somersaulting. They usually dive to a depth of about 90 m for about 3 minutes, but can reach depths of up to 260 m and remain underwater for up to 8 minutes. They often accompany ships, gliding on the bow wave.

What does it eat and how does it hunt?

Near the shores they feed on small schooling fish, in deep waters usually squid. They can organize collective hunts, driving fish near the surface of the water.

Offspring

They become adults at about 7 years of age. An adult female gives birth to a cub every 2-3 years.

Enemies in nature and threats from humans

The main threats are fishing gear, general ocean pollution, and declining food supply due to overfishing.

How they study

They have not been studied in Russian waters. Research on these dolphins is being carried out abroad.

COMMON PORGE PIG

length up to 1 m 80 cm

weight up to 65 kg

listed in the Red Book of Russia

WHITE-WINGED PORGE PORGE

length up to 2 m 10 cm

weight up to 220 kg

What does it look like

The common porpoise looks only slightly smaller than the white-winged porpoise, but in fact they have a significantly different mass. These two porpoises also differ in their coloration. The white-winged porpoise has a very bright two-tone coloration.

Number and habitats

Porpoises stay in shallow coastal waters. They are less common at depths of more than 200 m. In the Far East, they are common in the Seas of Japan and Okhotsk, off the coast of Sakhalin and the Kuril Islands. They can climb large rivers. Number of Far Eastern waters unknown.

How long does he live?

Porpoises live about 25 years.

Animal behavior

They usually live in groups, rarely gathering in herds of several hundred animals. They are often seen together with Pacific white-sided dolphins. Sometimes they accompany groups of fish-eating killer whales. As a rule, they do not jump out of the water. They can dive to depths of up to 220 m, and the white-winged porpoise can dive up to 500 m.

What does it eat and how does it hunt?

Porpoises feed near the bottom, preying on small schooling fish, squid and small crabs. They hunt at night.

Offspring

Porpoises give birth to their first pups at 3-5 years of age. Pregnancy lasts 10-12 months. The cub is fed milk for about 4-8 months. Many females give birth to 1 calf each year.

Enemies in nature and threats from humans

The greatest threats to porpoises come from fishing nets and disturbance caused by shipping and offshore mining. They are also affected by ocean pollution and declining food resources.

How they study

There are no special studies of porpoises in Russia. Their research is carried out abroad.

SEA LION

male length up to 3 m 30 cm, female length up to 2 m 70 cm

male weight up to 1100 kg, female weight up to 320 kg

listed in the Red Book of Russia

What does it look like

Steller sea lion is the largest eared seal with a massive body. He has small ears on his head. Adult males (cleavers) have a thickened neck and a furry mane. Males are much larger than females. The color of the sea lion varies depending on the sex and age of the animal. Newborns are dark in color. As animals age, they become lighter in color.

Number and habitats

Steller sea lion is a resident of the coastal waters of the North Pacific Ocean. The most famous rookeries and haulouts of sea lions are located on the islands of Tyuleniy and Moneron, in the area of ​​Cape Kuznetsov. On Sakhalin, they also annually arrange a haulout on the old breakwater in the city of Nevelsk. Largest number of sea lions Sakhalin region found on the islands of the Kuril chain. Several years ago, there was a sharp decline in the number of sea lions. IN Lately the decline of sea lions stopped and their numbers began to grow slowly. Now scientists count about 25,000 animals.

How long does he live?

The lifespan of sea lions is about 25 years.

Animal behavior

Each year the sea lion consists of two parts: sea lions spend half of the year on land, forming rookeries, the second half - in the sea, and during this time they practically do not go onto land. Animals make rookeries on hard-to-reach uninhabited islands or rocky capes. Staying at the rookery is accompanied by fierce fights between males. The animals constantly roar, so the noise from the rookery can be heard several kilometers away. At sea, animals live alone and in small groups. Sometimes sea lions are seen on the ice, where they behave very calmly. Almost nothing is known about the life of the sea lion during its maritime period.

What does it eat and how does it hunt?

The sea lion feeds more often at night and mainly on fish or cephalopods: squid, octopus and cuttlefish. To get food for themselves, sea lions can dive to a depth of more than 200 meters. Sometimes they go into rivers for fish. Recently, animals have begun to accumulate near fishing vessels, eating caught fish and fishing waste.

Offspring

Females can give birth to their first calf by 3-8 years of age. To give birth to their young, they go to the rookeries at the end of May or early June - after a few days they have pups. The mother usually feeds her baby with milk for several months and goes with it into the sea period. But it happens that the cubs stay with their mother and feed on milk for another 2-3 years; sometimes they suckle milk along with newborn puppies. A female can give birth to puppies every year, but she does this only with good nutrition.

Enemies in nature and threats from humans

Natural enemies of sea lions are killer whales. Many animals die in fishing nets. Also, general ocean pollution (including fragments of nets) is harmful to sea lions. Steller sea lion's food reserves are depleted and competition with humans for food increases.

How they study

Constant research of sea lion is carried out in all its habitats. In Russian waters, there has been a long-term tagging program for Steller sea lion pups, where the pups are branded on their sides, called a brand. In addition to observations at rookeries, scientists use satellite tags.

NORTHERN SEAL

male length up to 2 m 10 cm, female length up to 1 m 50 cm

male weight up to 320 kg, female weight up to 50 kg

What does it look like

The northern fur seal is a small eared seal. If you look closely, you can see small ears on the head. Cats have very thick fur. Adult males (cleavers) have a thickened neck and a furry mane. Males are much larger than females. In water, seals appear black, although they are actually dark brown to brown-yellow with gray patches.

Number and habitats

Northern fur seals are found only in the Far Eastern region. This is one of the most numerous species of seals in the Pacific Ocean. On Tyuleniy Island there are up to 112 thousand animals per season, on the Kuril Islands there are about 46 thousand animals.

How long does he live?

The northern fur seal lives up to 30 years.

Animal behavior

At sea, northern fur seals stay mostly alone or in small groups and are curious. On land they form huge rookeries for the birth of puppies. Young males form separate bachelor rookeries, where there are no females or newborn puppies at all. A cat can stay underwater for up to 7 minutes, and is capable of diving to a depth of up to 180 m. It sleeps on the surface of the water with its nose pointed out and its fins raised above the surface of the water. When swimming fast in the water, it can jump high out of the water, like dolphins.

What does it eat and how does it hunt?

The cat usually feeds in the predawn period and in the morning. During the day he rests. The diet includes a large number of different fish and cephalopods: squid, octopus, cuttlefish.

Offspring

Northern females fur seals can give birth to their first cub by 2-5 years. The birth of seals occurs in coastal rookeries. Newborn puppies are 60 cm long and weigh 4-5 kg. The mother feeds her cub with milk for 3-4 months, then leaves the rookery and the cub. The pup begins its adult life and after some time also leaves the rookery.

Enemies in nature and threats from humans

Newborn seals are in danger of being crushed by males who fight among themselves or chase a female, because the rookeries are very crowded. In nature, fur seals can be attacked by killer whales. Seals are adversely affected by general ocean pollution, fishing nets, and depletion of food resources that the seals feed on.

How they study

Northern fur seals are a well-studied species. Constant research of seals is carried out in all its habitats. In addition to observations at rookeries, scientists use satellite tags.

LARGA

length up to 1 m 80 cm

weight up to 150 kg

RINGED SEAL

length up to 1 m 70 cm

weight up to 80 kg

What does it look like

A small but fat seal. The seal's muzzle is elongated, similar in shape to a dog's. The body color is variegated with spots of various sizes. The belly is usually lighter in color and has fewer spots.

Number and habitats

These very numerous seals live in the North Pacific Ocean, in areas that are covered with ice during the winter.

How long does he live?

These seals live 35-40 years.

Animal behavior

In winter they lie on the ice. They usually live alone or in small groups. The ringed seal keeps holes in ice all winter so that they do not freeze, through which it dives and gets food. In summer, seals rush to the mouths of spawning rivers, where they form large breeding grounds. Seals lie on sandy or rocky islands and spits exposed during low tide. They usually dive to a depth of about 45 m for about 8 minutes, but can reach depths of up to 150 m and remain under water for up to 23 minutes.

What does it eat and how does it hunt?

Ringed seals and seals feed mainly on fish, octopuses and small crabs.

Offspring

Females can give birth to their first cub at 4-5 years of age. At the end of winter - beginning of spring, one cub is born. Females feed their cubs with milk for only 3-4 weeks, then the female leaves the cub. From this time the cub begins adult life.

Enemies in nature and threats from humans

The main enemy of seals in nature is the killer whale. A common threat to animals living on ice is a decrease in ice area as a result of global warming. Animals suffer from general ocean pollution and die when they become entangled in fishing nets. Sometimes seals are killed illegally by fishermen trying to protect their catch. Also Larga and ringed seal They are commercial species, so these seals are hunted by humans.

How they study

Larga and ringed seals are fairly well studied species. Scientists have enough data on numbers, distribution, reproductive characteristics and nutrition.

SEA HARE (SEA HARE)

length up to 2 m 20 cm

weight up to 320 kg

What does it look like

The body is massive. From a distance, the lying animal looks like a stump of a thick log. The wool is plain without small spots or patterns. The color can be very different - from gray to brown. The belly and head are lighter. The head and neck may have a reddish tint due to the seal digging in the mud. The head is small with lush, long whiskers called vibrissae. The front flippers are very short, square-shaped, with claws.

Number and habitats

It lives in the Sea of ​​Okhotsk, where there are two groups of these seals (populations). There are about 40 thousand animals in the Sakhalin population, and about 160 thousand in the North Okhotsk population. During the period of birth of puppies (March-May), bearded seals form rookeries on the ice in the northern part of the Sea of ​​Okhotsk, as well as off the eastern coast of Sakhalin. In summer, sealed seals stay in the coastal zone of the sea, roosting on rocks and shallows. Sometimes it swims up rivers for tens of kilometers.

How long does he live?

The bearded seal lives for approximately 30 years.

Animal behavior

On drifting ice, males lie alone. The cubs lie instead with their mothers. In summer, bearded seals gather in rookeries where dozens of animals are present at the same time.

On ice, the sealed seal usually lies at the edge of the ice floe or near a thawed area, with its head towards the water. When in danger, it quickly goes into the water. It does not jump onto the ice, but climbs heavily, hitting the water with its back flippers. It swims on the surface of the water, exposing its head and back.

What does it eat and how does it hunt?

Can stay under water for up to 20 minutes. It dives to the bottom because it feeds mainly on bottom and benthic animals: crabs, shrimp, mollusks, worms, fish.

Offspring

A female can give birth to her first cub at 3 - 7 years of age. From this point on, the female gives birth to one puppy almost every year. Pregnancy lasts about 11 months. Cubs are usually born from mid-March to early May. The length of a newborn puppy is up to 1 m 20 cm. Puppies do not have white coat, that is, they do not have white fur, but they have a color like an adult seal. The cub feeds on mother's milk for only a month. Then the female leaves him, and the cub begins an independent life.

Enemies in nature and threats from humans

The main enemy of the bearded seal in nature is the killer whale. This species is also a commercial species and is hunted by humans. Big threat comes from climate change: bearded seals give birth to their young on the ice, and every year there is less and less ice.

How they study

No special research has been carried out on the bearded seal; it is being studied along with other seals.

lionfish

length up to 1 m 90 cm

weight up to 90 kg

What does it look like

The body of the lionfish is slender and elongated. Big black eyes. Adult males have four wide white stripes on their dark body. Females are less brightly colored.

Number and habitats

Lives in the northern part of the Pacific Ocean. Lives far from the coast, at great depths. Cubs are born exclusively on ice, so lionfish breeding grounds are located where there is ice.

How long does he live?

The lionfish lives for about 30 years.

Animal behavior

Lionfish usually live far from the coast. There is practically no access to the shore. They spend half the year on the open sea, and during the ice season they like to relax on ice floes. It is not yet known how the lionfish behaves during the non-ice period.

During the birth of puppies, they are kept on ice floes alone or in groups of up to 3 animals. He jumps onto the ice with a strong, light jump, without touching the ice floes. It moves quickly on the ice, with snakelike movements. On ice it usually lies with its head to the water or sideways. It dives only head down, completely silently, without a splash.

What does it eat and how does it hunt?

When living on ice, it feeds on a variety of fish that live far from the coast, crabs and squid. They can dive to depths of up to 600 m.

Offspring

Female lionfish can give birth to young at the age of 1-4 years. Pregnancy lasts about a year. Cubs are born from late March to early May. One cub is born, 80 - 90 cm long. The puppy feeds on milk for 20 - 30 days, then the female leaves the cub, and it begins an independent life.

Newborn puppies are covered with thick white fur. After molting, they become dark gray, and by 2-4 years, light stripes appear on their body.

Enemies in nature and threats from humans

The main enemy of the lionfish in nature is the killer whale. Also, a common threat to animals living on ice is a decrease in ice area as a result of global warming. In addition, for lionfish, which spend most of their time in the open sea, there is a threat of death in fishing nets.

How they study

Basic information about this species was accumulated during the period of active hunting in the second half of the last century. Recently, scientists have been trying to obtain more up-to-date information and conduct research using satellite tags.

SEA OTHER

length up to 1 m 70 cm

weight up to 45 kg

listed in the Red Book of Russia

What does it look like

The sea otter is very similar to the river otter, but is larger in size. Thanks to its flexible, elongated body, the animal swims well. The front legs are short, but have very grasping fingers with retractable claws, and the hind legs are more like flippers, due to the fact that the fingers are connected by thick membranes. The sea otter's tail is small but strong. The fur is very thick, which helps keep water out of the body, so the sea otter does not freeze in winter. Has poor vision and hearing.

Number and habitats

About 8,000 sea otters live in Russian waters. They live in the shallow coastal waters of the Kuril and Commander Islands and the coastal waters of the Kamchatka Peninsula.

How long does he live?

Sea otters live from 9 to 11 years.

Animal behavior

The sea otter usually swims on its back with its paws exposed to the air, but it can also swim on its stomach, while constantly changing position: stomach - back, stomach - back. It takes care of its fur, rests and feeds its cub only on the surface of the water or goes out onto rocks or sand spits. The front paws are used for obtaining food and grooming the fur. Dives shallowly and not for long. They prefer to live in small families. But during rest they swim in large groups.

What does it eat and how does it hunt?

Sea otters feed on sea urchins, shellfish, crabs and fish. It is the sense of smell that allows sea otters to hunt successfully. Such an acute sense of smell is provided by vibrissae (whiskers). Sharp teeth help crack crab shells and mollusk shells.

Offspring

Sea otters are very good parents, devotedly caring for their offspring. The female bears one cub. A puppy is born in spring. Childbirth occurs on the shore and in the water. The cub lives with its mother for 5–12 months.

Enemies in nature and threats from humans

In nature, the enemies of sea otters are killer whales, white sharks, and sea lions. People have always persecuted sea otters for their fur and skin. But the main enemy of sea otters is sea pollution with oil products. If a sea otter's fur becomes contaminated with petroleum products, the fur will begin to become completely wet and the sea otter will die from cooling.

How they study

The sea otter is a fairly well-studied species. Sea otter populations on the Commander and Kuril Islands are constantly monitored.

Drawings by A. Chernyavskaya.

Descriptions of animals are compiled based on materials:

1. Artyukhin Yu.B., Burkanov V.N. Seabirds and mammals of the Russian Far East. Field guide.

2. Burdin A.M., Filatova O.A., Hoyt E. Marine mammals of Russia: a reference guide.

3. Melnikov V.V. Field guide to marine mammal species for Pacific waters.

Some marine animals can survive without oxygen for quite a long time. For example, for a sperm whale diving to a depth of almost a kilometer, the supply of air that it inhales before this is quite enough to complete such a deep dive, and seals feel quite comfortable for at least half an hour without life-giving gas.

on this topic

For a long time, scientists could not understand how they were able to do this, but quite recently, British experts seem to have figured out this issue. Paradoxically, electricity plays a major role in this. The researchers set out to study the composition of myoglobin, a protein that binds oxygen necessary for the functioning of mammalian muscles. It turned out that in animals such as seals and whales, it has a truly unique property of accumulating large amounts of oxygen, without any damage to the body. Experiments conducted by Dr. Michael Berenbrink, working at the University of Liverpool and the Institute of Interactive Biology and published in the scientific journal Science, allowed him to conclude that marine animals are able to accumulate much greater amounts of oxygen than land animals, which is explained primarily by the characteristics of their natural habitat. According to the scientist, his main goal was to understand why, at high concentrations in the bodies of marine animals, proteins do not “stick together.”

It turned out that their molecules have the same electrical charge (positive), and therefore repel each other. This “physico-chemical trick” allows marine animals to accumulate large amounts of oxygen, since the molecules “work” autonomously in this regard and do not waste their resources interacting with each other. According to Dr. Berenbrink, they, like the same poles of different magnets, repel each other. It is this feature, which appeared as a result of evolution, that allows marine animals to store oxygen in much larger volumes and much faster than land animals are able to do.

Leading researchers are of the opinion that this important discovery will allow them to thoroughly understand what changes have occurred in mammals as a whole and in their individual organs throughout their development. When the habitat changed, the breathing processes changed significantly, allowing animals to exist in completely new natural conditions. It should be noted that this happened over millions of years evolutionarily, and basically marine animals retained the original method of assimilation of oxygen, significantly “modernizing” and improving it.

Elephant seals not only have an extraordinary appearance, but also amazing superpowers. It turns out that these marine mammals are record holders for holding their breath and can dive to considerable depths. Could you go without breathing for two hours? It’s hard to even wrap your head around these numbers, but for elephant seals this is quite common. How do they do this?

Elephant seals are a genus of large marine mammals that includes only two species: the northern elephant seal and the southern elephant seal. It is noteworthy that the characteristic appearance with big nose Only males have it. These two species are largely similar in lifestyle, but differ in distribution. Northern elephant seal lives off the western coast North America, and its southern relative is off the coast of Antarctica.

Northern elephant seal

Southern elephant seal

It is the southern elephant seal that is outstanding in many respects. It is larger than its northern relative: the weight of males reaches 3-5 tons, although females are much smaller - only 400-900 kg. These amazing marine mammals are capable of diving to depths of up to 1,500 meters, although the average is about 500 meters, which is also impressive. But in order to dive to such depths, you need to hold your breath. And then scientists discovered something simply amazing: the southern elephant seal is able not to breathe for two hours and still feel great. Of course, 2 hours is an absolute recorded record, and on average, as observations show, this species of elephant seal dives to a depth of up to 500 meters.

Such superpowers are due to the body structure of southern elephant seals. Elephant seals are inhabitants of cold seas, and their body consists of 30-40% fat deposits. This circumstance, according to scientists, allows elephant seals to dive to significant depths, where pressure exceeds 10 atmospheres, because fat almost does not compress under pressure.

Other physiological feature elephant seals have a peculiar structure of nostrils, which open only at the moment of inhalation and exhalation, and when the animal is under water, they are tightly closed. But the most interesting thing in the body of these animals is the structure circulatory system.

Heartbeat Elephant seals slow down greatly when diving. If on land his heart beats 60-70 times per minute, then during a dive to a significant depth this figure is only 10-30 beats. At the same time, the consumption of oxygen is reduced, which, in the same quantity, flows only to the heart and brain. Biologists also managed to find out that there are significantly more red blood cells, which are responsible for transporting oxygen in the body, in the body of elephant seals than in other mammals. These are such amazing animals - southern elephant seals!