The blue angel is a species of gastropod mollusks common in the seas of all oceans of the tropical belt. The body length is 5-40 mm. On the sides, perpendicular to the axis of the body, there are three groups of cerata - finger-shaped outgrowths, into which branches of the hepatopancreas (digestive gland) enter. The length of the cerata varies significantly in each group, with the longest ones located on the dorsal side. The presence of long outgrowths is considered as one of the mechanisms for increasing buoyancy. The main body tone is silver. The oral tentacles, rhinophores and the lower surface of the cerata are painted in an intense blue color. The dorsal side of different mollusks varies from dark blue to brown. The leg is framed by a blue stripe along the edge. The angel attacks the jellyfish, takes the poison from them and eats them. The sea dragon does not crawl away from the found jellyfish, because it serves as a home and even an incubator! The mollusk attaches its eggs directly to the half-eaten jellyfish. Blue dragons are hermaphrodites, but they cannot self-fertilize.
An uncovered clam.
Sea lilies are one of the classes of echinoderms. Bottom animals with a body in the form of a cup, in the center of which there is a mouth, and a corolla of branching rays (arms) goes up. An attachment stalk up to 1 m long extends down from the calyx of stalked sea lilies, growing to the ground and bearing lateral appendages. Sea lilies are the only echinoderms that have preserved the body orientation characteristic of the ancestors of echinoderms: their mouth is turned up, and the dorsal side is turned to the ground surface. As with all echinoderms, the body structure of sea lilies is subject to five-ray radial symmetry. The expanded corolla of the sea lily forms a net for trapping plankton and detritus. Hands on your inner (oral) the sides have mucosal-ciliary ambulacral grooves leading to the mouth; along them, food particles captured from the water are transferred to the mouth opening. Stalked sea lilies lead a sedentary lifestyle and are found at depths from 200 to 9700 m. Stemless, they are most diverse in the shallow waters of tropical seas, often brightly and variegately colored. Approximately 65 % of the stemless sea lilies live at a depth of less than 200 m. In the tropical part In the Pacific Ocean, up to 50 of their species can live on one reef. Stemless lilies are able to detach from the substrate, move along the bottom and float due to the movement of the hands. All sea lilies are passive filters that filter out a nutrient suspension from the water: protozoa (diatoms, foraminifera), invertebrate larvae, small crustaceans and detritus.
The huge head makes up to a third of the total length of the body, has the appearance of a rectangle. The lower jaw is set with large teeth, of which there are usually 20 pairs, but there are also 8 pairs, there are only 1-3 pairs of teeth on the upper jaw, and often there are none at all. Each tooth weighs about one kilogram. The lower jaw can open vertically downwards, at 90 degrees. The mouth cavity is lined with rough epithelium, which prevents the prey from slipping out. The sperm whale's body expands and becomes thick in the middle, almost round in cross section. Then it narrows again and gradually turns into a caudal stem. The caudal fin of a sperm whale is up to 5 m wide. The sperm whale's skin is wrinkled and folded, and usually has a dark gray tint. Sperm whales grow all their lives, so the older the whale, the larger it is, as a rule; at the same time, males are almost twice as large as females. Males are 18-20 m long and weigh from 40 to 70 tons. The vocal signals of the sperm whale are generally similar to those of other whales. These are three types of sounds — moaning sounds, clicks and a quick crackle, similar to the sound of a mechanical typewriter, and creaking.
Most of the volume of the head is occupied by a spermaceti sac located above the upper jaw, a spongy mass of fibrous tissue impregnated with spermaceti (a complex composition of adipose tissue). It is believed that this substance and the organ in which it is stored perform a number of tasks at once. The bag helps sperm whales make full use of echolocation by amplifying ultrasonic waves, liquid fat provides the necessary level of buoyancy, which helps whales dive to gigantic depths and surface from them. It is known that male sperm whales collide with each other at a speed of 17 km / h, trying to demonstrate dominance, in such cases the main impact falls on the reservoir with fat. There were cases when whalers themselves became victims of sperm whales, as the latter rammed and sank ships.
The sperm whale has one of the largest ranges in the entire animal world. It is common throughout The world Ocean, except for the northernmost and southernmost cold regions. Sperm whales are more common in warm waters than in cold ones.
Sperm whales are gregarious animals. During migrations, the whale's speed rarely exceeds 10 km/h, and the maximum whale speed is 37 km/h. When feeding, sperm whales can act in well-organized groups of 10-15 individuals, collectively herding prey into dense groups. At the same time, the whales show a high level of interaction. Collective hunting took place at depths up to 1,500 m. Sperm whales often live to be 60 years old. The sperm whale's unique ability to dive extremely deep is known. He dives deeper than any other air-breathing animal. Some sources indicate the possible ability of the sperm whale to dive up to 3000 m. The whale's body is well adapted for such dives due to a number of anatomical features. The enormous pressure of water at depth does not harm the whale, since its body is largely made up of fat and other liquids that are very little compressible by pressure. The lungs of a whale are half as large relative to the body volume as those of land animals, so the sperm whale's body does not accumulate excess nitrogen, which happens in all other living creatures when diving to great depths. Caisson disease, which occurs when nitrogen bubbles enter the blood during ascent, never happens in a sperm whale, since the sperm whale's blood plasma has an increased ability to dissolve nitrogen, preventing this gas from forming microbubbles. The whale stores 41% oxygen in its muscles, while only 9% is stored in its lungs. In addition, the sperm whale's metabolism changes very significantly during deep dives. The pulse drops to 10 beats per minute, and the blood flow is greatly redistributed. The sperm whale actively uses high-frequency and ultrasonic echolocation to detect prey and orient itself. The latter is especially important for him, since this whale plunges to a depth where there is no lighting at all. Sperm whales are polygamous; during the breeding season, males form harems — 10-15 females stay near one male. Sperm whales can give birth at any time of the year.Pregnancy lasts from 15 months to 18 months and sometimes more. The cub is born alone, 3-4 m long and weighing about a ton
![One of the most interesting features in the sperm whale's diet is its eating of giant cephalopods, which it encounters at great depths. Huge squids occupy an important place in the diet of the sperm whale; in any case, it is the sperm whale that is the main natural enemy of giant cephalopods[66]. This applies, in particular, to the largest squid of the genus Architeuthis, whose length can be more than 10 m. Squid suckers leave round marks with a diameter of up to 20 cm on the skin of a sperm whale, at the same time, even the largest squid known to science, at the same time, even the largest squid known to science (even those whose length, together with tentacles, reached 10 meters), the diameter of the suckers did not exceed 5 cm. Most likely, the squid left sucker prints when the sperm whale had not yet reached the full size of an adult whale, and then, when the sperm whale grew up, the scars from the suckers stretched to 15-20 centimeters in diameter](/upload/test_stable/c13/c13ed8cda16ec0e3ec76a88ca362b599.webp "One of the most interesting features in the sperm whale's diet is its eating of giant cephalopods, which it encounters at great depths. Huge squids occupy an important place in the diet of the sperm whale; in any case, it is the sperm whale that is the main natural enemy of giant cephalopods[66]. This applies, in particular, to the largest squid of the genus Architeuthis, whose length can be more than 10 m. Squid suckers leave round marks with a diameter of up to 20 cm on the skin of a sperm whale, at the same time, even the largest squid known to science, at the same time, even the largest squid known to science (even those whose length, together with tentacles, reached 10 meters), the diameter of the suckers did not exceed 5 cm. Most likely, the squid left sucker prints when the sperm whale had not yet reached the full size of an adult whale, and then, when the sperm whale grew up, the scars from the suckers stretched to 15-20 centimeters in diameter")
One of the most interesting features in the sperm whale's diet is its eating of giant cephalopods, which it encounters at great depths. Huge squids occupy an important place in the diet of the sperm whale; in any case, it is the sperm whale that is the main natural enemy of giant cephalopods[66]. This applies, in particular, to the largest squid of the genus Architeuthis, whose length can be more than 10 m. Squid suckers leave round marks with a diameter of up to 20 cm on the skin of a sperm whale, at the same time, even the largest squid known to science, at the same time, even the largest squid known to science (even those whose length, together with tentacles, reached 10 meters), the diameter of the suckers did not exceed 5 cm. Most likely, the squid left sucker prints when the sperm whale had not yet reached the full size of an adult whale, and then, when the sperm whale grew up, the scars from the suckers stretched to 15-20 centimeters in diameter
The sperm whale, like all toothed whales, is a predator. The basis of its diet consists of two groups of animals — cephalopods and fish, and cephalopods absolutely predominate.Cephalopods make up about 95% of the total (by weight) the food consumed by sperm whales and fish is less than 5%. An adult sperm whale needs to eat about a ton of cephalopods per day for normal nutrition. The sperm whale catches its prey at a depth of at least 300-400 m, where it has almost no food competitors, with the possible exception of some beaked whales
There are different estimates of the current number of sperm whales in the world's oceans. Most often, estimates converge on the figures of 300-450 thousand. According to estimates provided by the International Union for Conservation of Nature, in 2003, sperm whales on Earth were from 30 to 50% of the number that lived in 1922. The recovery in the number of sperm whales has been observed since the 1980s, when their fishing was finally stopped, but it is extremely slow. Cubs and even adult female sperm whales can be attacked by killer whales — researchers have recorded cases when killer whales inflicted severe wounds on adult females or even tore them apart. Some scientists doubt the ability of killer whales to overcome adult sperm whales (even a herd of females with cubs, acting together, can drive away killer whales). Nevertheless, special studies conducted in 1999 led to the conclusion that attacks with fatal outcomes for sperm whales still happen — for example, a study of the fresh skeleton of a 9.8-meter female sperm whale showed that the whale was torn apart by killer whales. But in general, according to general estimates, the threat to sperm whales from killer whales is very small. Among the causes of natural mortality of these whales are myocardial infarction, stomach ulcer, and bone necrosis, which can occur from the penetration of microscopic nitrogen bubbles during decompression during the whale's ascent from the depths. The sperm whale, like other large whales, grows quite heavily with various crustaceans, which, however, do not cause any damage to the whale's body. This whale is susceptible to infestations of endoparasites, of which the most notable is a giant roundworm (up to 8.5 m long) living in the placenta of females. Marine pollution is an important factor affecting the number of sperm whales in a number of areas of the world Ocean. The catastrophic oil leak in the Gulf of Mexico in the summer of 2010, according to some non-governmental environmental organizations, had a serious negative impact on the local sperm whale population. Sometimes sperm whales are killed or seriously injured in collisions with ships. The death of sperm whales in fishing nets is very rare, but still such cases are recorded. This factor plays the greatest role in The Mediterranean Sea. There have been cases when sperm whales caused damage to fish catches by devouring large fish that had already been hooked during industrial fishing. This behavior of sperm whales has been recorded in Alaska. Fishermen who lost up to 20% of their catch due to the fault of sperm whales even turned to scientists for help
For centuries (until the middle of the XX century), the sperm whale was the most important object of whaling before its prohibition. Until 1948, about 5,000 animals were harvested annually. After that, production volumes increased sharply to 20 thousand heads per year, mainly in the North Pacific and in the Southern Hemisphere. Sperm whale production was severely restricted in the second half of the 1960s, and in 1985, sperm whales, along with other whales, were completely taken under protection. Sperm whale mining in the XVIII—XIX centuries was especially developed in the USA. Its center was Nantucket, which at one time was probably the largest whaling port in the world - up to 150 whaling schooners were assigned to it. With such intensive fishing, male sperm whales were knocked out very badly, which negatively affected not only the livestock, but also the average size of these whales — the average length and weight of sperm whales became noticeably smaller due to the destruction of the largest specimens. The main product of the sperm whale fishery at all times was fat, 12-13 tons were obtained from one sperm whale. Amber is a solid wax—like substance of gray color, formed in the digestive tract of sperm whales, having a complex layered structure. Amber has been used since ancient times and until the middle of the XX century as an incense and as a valuable raw material in the manufacture of perfumes. Spermaceti, it was used to make ointments, lipsticks, etc.; candles were often made. Sperm whale teeth in Europe and North America at the time of intensive whale mining served as a very expensive ornamental material, valued on a par with mammoth tusk and walrus tusk. Sperm whale meat, like the meat of other toothed whales, has a strong, not very pleasant smell compared to the meat of baleen whales, therefore it was extremely rarely eaten by humans. Whaling before its mechanization was associated with increased risk, largely due to the fact that wounded sperm whales, becoming enraged, attacked boats with whalers, and often the whaling ships themselves. The strength of a sperm whale, even a wounded one, was usually enough to smash a boat with a single blow of the head or tail in a retaliatory attack. Thus, sperm whales account for many lives of whaling sailors. Therefore, the extraction of sperm whales was considered a particularly difficult and dangerous occupation among whalers. An incident became widely known when, in 1820, an enraged sperm whale twice headbutted the American 230-ton whaling ship Essex and sank it. At the time of the sinking, the ship was thousands of kilometers from the shore. The crew of the Essex managed to escape and land on a desert island, but people suffered incredible hardships (including cannibalism against comrades who died of hunger or thirst in boats), as a result, only 8 out of 21 sailors survived. The sperm whale is the only whale whose throat theoretically allows you to swallow a person whole without chewing (and, generally speaking, the only animal capable of doing this). However, despite the high number of deaths when hunting sperm whales, these whales seem to have exceptionally rarely swallowed people who got into the water. The only relatively reliable case occurred in 1891. A sperm whale crashed a dinghy from a British whaling schooner, harpooner James Bartley, went missing and was presumed dead. The sperm whale that sank the dinghy was killed a few hours later. By morning, the whalers, having reached the inside of the whale, found James Bartley, who was unconscious, in his stomach. Bartley survived, although not without health consequences. Bartley had to leave whaling, but he was able to earn good money by showing himself at fairs as a man who had been in the belly of a whale.Despite the fact that the incident with James Bartley is usually considered authentic, it remains unclear how a person could survive after spending fifteen hours in the stomach of a whale — without access to air and in an acidic environment. It is possible that the side of the whale and its stomach were pierced by a harpoon and air entered the stomach through this wound. Some sources reasonably doubt the truth of this incident with reference to another case when a sperm whale in 1893 also swallowed a whaler, but the swallowed sailor died immediately from injuries and suffocation, and his body was severely corroded by acidic gastric juice.
A piece of sperm whale skin covered with traces of giant squid suckers
A way to protect cubs by adult sperm whales
A sperm whale tooth with a carved image
Illustration for Herman Melville's novel "Moby Dick" published in 1892
The Japanese giant spider crab, although not the heaviest in the underwater world, is however the largest known arthropod. A well-calcined shell is only about 40 cm, but the total length of adult individuals can be almost 5 meters from one tip of the cheliped (claws with claws) to the other when stretched. The whole crab weighs up to 19 kg. Spiny and short tubercles (growths) cover the carapace, which varies from dark orange to light brown in color. The shell tends to remain the same size throughout adulthood, but the claws lengthen significantly as the age of the crab increases. Spider crabs are known for having long, thin limbs. The walking claws end with moving parts curved inwards at the tip of the walking limb. Although long legs, they are often weak. One study reported that almost three quarters of these crabs lack at least one limb, most often one of the first walking legs. This is because the limbs are long and poorly connected to the body and tend to come off due to predators and nets. Spider crabs can survive if up to 3 walking legs are missing. Walking legs can grow back during regular molts.
The habitat of the Japanese arthropod giant is limited to the Pacific side of the Japanese Honshu Islands from Tokyo Bay to Kagoshima Prefecture, usually at a latitude of 30 to 40 degrees north latitude. Japanese spider crabs most often live on the sandy and rocky bottom of the continental shelf at depths up to 300 meters. They like to hide in vents and holes in the deep parts of the ocean. Temperature preferences are unknown, but spider crabs are regularly found at a depth of 300 m in Suruga Bay, where the water temperature is about 10°C. Young individuals tend to live in shallower areas with higher temperatures.
The spider crab is an omnivorous scavenger, consuming both plant substances and parts of animal origin. He is not an active predator. Basically, these large crustaceans, as a rule, do not hunt, but crawl and collect dead and decomposing matter along the seabed. Sometimes they eat algae and live shellfish. Although giant spider crabs move slowly, they are able to hunt small marine invertebrates, which they can easily catch. Some individuals are cleaners of the ocean floor from decaying plants and algae, and some open shellfish shells. The crustacean has a mild character, despite its ferocious appearance.
Spider crabs are very calm creatures, spending most of their days searching for food. They roam the seabed, moving casually over rocks and potholes. But this marine animal does not know how to swim at all. Spider crabs use their claws to tear apart objects. These spider crabs shed their shells, and new ones grow even bigger with age. One of the largest spider crabs ever caught was only forty years old, so it is unknown what size they may have when they reach a greater age. At the age of 10, the spider crab becomes sexually mature. Japanese laws prohibit fishermen from catching M. kaempferi during the mating season in early spring, from January to April, in order to preserve natural populations and allow the species to spawn. During incubation, females carry eggs on their back and lower body until they hatch. The mother stirs the water with her hind legs to saturate the eggs with oxygen. After the eggs are hatched, parental instincts are absent, and the larvae are left to fend for themselves. Female crabs carry fertilized eggs attached to their abdominal appendages until tiny planktonic larvae hatch. The development of planktonic larvae depends on temperature and takes from 54 to 72 days at 12-15 °C. Due to the mild nature of spider crabs, they are often found in aquariums. They rarely come into contact with humans, and their weak claws are quite harmless.
An adult spider crab is quite large, so it has few predators. He lives deeply, which also affects security. Young individuals try to decorate their shells with sponges, algae or other objects suitable for camouflage. However, adults rarely resort to this method because their large size deters most predators from attacking. Although spider crabs move slowly, they use their claws against small predators. The armored exoskeleton helps the animal to protect itself from larger predators. But despite the fact that these spider crabs are massive, they still have to beware of an accidental predator such as an octopus. Japanese fishermen continue to catch spider crabs, despite the fact that their numbers are declining. Scientists fear that its population may have declined significantly over the past 40 years. These crabs are often served as a treat during the respective fishing seasons and eaten both raw and boiled. Because the legs of the spider crab are very long, researchers often use tendons from the legs as a subject for study. In some parts of Japan, it is customary to take and decorate the shell of an animal.
This crab specimen from the American Museum of Natural History measures 3.8 meters (12 feet) across its outstretched legs
The shell of a turtle is characterized by an oval shape, while its length can reach almost 2 meters, although there are mostly individuals with a shell length of no more than 1 meter. Attention should be paid to the structure of the shell, which consists of flaps that fit snugly together. The head of the reptile is partially covered with the same shields. The eyes are relatively large, almond-shaped, with round pupils.There is a small claw at the end of each flipper. On average, adults weigh within a hundred kilograms, but this is not the limit, as there are individuals weighing up to 200 kilograms. It should be noted that the record weight of the green turtle was registered, which amounted to almost half a ton.
Sea turtles prefer to lead a secluded lifestyle, so it is almost impossible to meet turtles in a group. Scientists still cannot figure out how turtles navigate the vastness of the world's oceans. They are able to gather in a certain place on the same day to reproduce their own kind.After being born, turtles for decades, having traveled tens of thousands of kilometers across the expanses of the World Ocean, unmistakably find the place where they were born. Sea turtles are non–aggressive and trusting marine life that try to stick to the coastal zone, where the depth is no more than 10 meters. Being at rest or in a state of sleep, turtles do not appear on the surface of the water for several hours. With the help of their forelimbs-flippers, turtles can reach speeds of up to 10 km / h, which is not bad for such marine life. As they grow older, turtles begin to move from the depths closer to the coastal zone. Living in a natural environment, green turtles can live up to 80 years, but turtles live much less in captivity.
The female lays up to a hundred eggs, after which the hole is filled with sand and leveled. In this way, she masks her masonry. In one season, the female lays 50-100 eggs 7 times. The incubation process lasts for 2 months and several days, after which small turtles begin to emerge from the eggs, breaking through the shell. Most of the nests are ruined, so only a few manage to be born.As soon as the little turtles manage to free themselves from the shell, they rush through the sand to get into the aquatic environment, so as not to turn out to be lunch for some predators. In fact, not many of them are lucky and some of them don't even make it to the surf line. Even those kids who managed to get into the water will not be lucky for many, as they will find many surprises here, from which it is difficult to hide. At first, small turtles have to hide in the depths of the sea, carefully disguising themselves. The diet of young turtles does not consist only of plant foods. They also feed on jellyfish, mollusks, crustaceans and plankton. As you get older, your diet also changes, as plant-based foods begin to predominate. During the 7-10 years of the turtles' life, the process of solidification of the shell takes place. A hard shell is at least some kind of a guarantee that there are not so many hunters for turtle meat.
The comfortable living conditions of the green turtle are associated with a depth of no more than 10 meters, with a sufficient amount of algae for food, as well as with a rocky bottom. At such a depth, the water warms up well, which attracts green turtles, regardless of the geographical location of these places. Marine green turtles prefer to live in the waters of the tropics and subtropics, as well as in the waters of the Pacific and Atlantic Oceans. Among the rocks, turtles hide from natural enemies, rest, and caves serve as a home for turtles for many years.
Many travelers have put a lot of effort into exploring the New World and the Caribbean Sea, while they massively exterminated these marine life, going on trips to discover new lands. Turtles were destroyed in large numbers, replenishing food supplies. Their dried and dried meat was loaded onto ships. Soup was made from this meat. Soup made from these turtles even nowadays belongs to delicatessen dishes. That is why green turtles are on the verge of extinction in our time.While in the reserve, tourists are forbidden to approach the turtles closer than 100 meters. Eggs laid by turtles are placed in incubators, after which the newly born babies are released into safe waters, and when they get stronger. Since turtles are listed in the Red Book, turtle hunting and egg extraction are prohibited in their nesting sites. In addition, it is forbidden to conduct any kind of business, including business activities. The program has yielded its results and experts are confident that the number of green turtles has grown so much that it inspires hope that green turtles will not disappear from the face of the earth in the near future.
Despite the relative rarity of attacks, the fear of them is great due to the numerous descriptions of individual cases, as well as thanks to literary works and horror films like the Jaws movie series. Up to 100 million sharks are still killed by humans every year. The most valuable ocean predator, which plays a vital role in maintaining a healthy state, is being destroyed The world ocean.
Contrary to popular belief, only a few shark species are dangerous to humans. Of the more than 360 species, only 4 have been seen in a significant number of unprovoked fatal attacks on humans: white, tiger, blunt-nosed and long-winged sharks. However, despite the fact that these marine predators are capable of attacking humans, they are generally not aggressive and there are numerous photos and videos of them taken by unprotected divers in open water. For example, the French film Oceans contains footage of a man swimming freely next to sharks.
Like most natural hunters, sharks feel a sense of curiosity when they encounter something unusual on their territory. Deprived of limbs with sensitive fingers, they use the only available way to study an object — to bite. These bites are known as exploratory bites. As a rule, in such an attack, the shark swims away after the first bite. For example, attacks on surfers are considered to be exploratory bites, since a shark may well make a mistake — the silhouette of a surfboard with arms and legs hanging from it is very similar from below to its usual prey — a seal, a sea lion or a turtle. And yet such "research" can result in severe consequences for a person, especially if it is such a powerful predator as a white or tiger shark. Despite some rare exceptions, it is believed that sharks do not attack people for the purpose of eating them. Humans are not the source of high-fat meat that sharks need to meet their needs for a huge amount of energy to control a large and powerful body. Rather, they will prefer fat seals and sea lions instead of a relatively bony man. But because of its poor eyesight (some species) and muddy water, the shark sees these animals in the silhouettes of people swimming on the surface of the sea (especially on a surfboard).
Shark behavior is usually impossible to predict. They can swim listlessly for a long time next to each other, and then suddenly attack the swimmer. This attack can turn out to be either a simple exploratory bite or an overt attack. There is no way to completely eliminate the possibility of a shark attack while a person is in the water, but some precautions can be taken to reduce the risk.:
Sharks usually make one swift attack, and then wait, allowing the victim to die or exhaust himself before starting to eat. This protects the shark from damage from an injured and active victim, but at the same time gives people time to get out of the water and stay alive. The shark's electrical sense organs, called ampoules of Lorenzini, are capable of detecting electrical impulses produced by muscles during contraction. According to one version, the electric receptors of a shark detect electrical impulses of movement of a wounded fish during someone's fishing or spearfishing, and this may become a reason for a mistaken attack on a person. In addition, the electrical impulses of a bathing person can also be perceived by a shark as movements of a wounded animal, that is, easy prey. But their attack usually does not begin immediately — first the shark studies the person, swimming around, and then it can disappear and suddenly appear. There are usually two types of shark attacks: 1 Provoked attack — when a person first comes into contact with a shark. The victims are usually curious divers who do not follow basic precautions. 2 Unprovoked attack: 2.1 A sharp single bite. As a rule, it occurs in the area of beaches where the shark hunts fish. The shark grabs, immediately releases its jaws and immediately swims away. The feet or legs remain damaged, but usually these bites are not very significant and extremely rarely lead to death. In this case, surfers often become victims: their arms or legs hang from the board into the water. 2.2 A surprise attack usually occurs in deep water areas. In these cases, the shark sees its prey in front of it, sneaks up unnoticed and appears in front of the swimmer out of nowhere. The result can be serious injury or death, especially if the shark continues to attack. 2.3 Blow-bite. In such an attack, the shark circles around the victim, actually hitting her with her head or body before each bite. As with a surprise attack, the shark can attack repeatedly. Serious injury or death may also result from such an attack.
The blue whale is a marine mammal from the infraorder cetacea, belonging to the family of striped whales of the order baleen whales. The blue whale has an elongated, slender body — the ratio of length to body thickness is much greater than that of other baleen whales. The head is large, making up about 27% of the body length. When exhaling, the blue whale releases a vertical fountain of water in the form of a narrow, upward-expanding cone or column up to 9 and even 10 m high. Like all striped whales, the blue whale has a large number of longitudinal stripes or furrows on the lower part of the head, which continue on the throat and belly. They are formed by folds of the skin and play a dual role — they help the whale's throat to stretch strongly when swallowing a large volume of water with food, and also improve the hydrodynamic properties of the whale's body. The blue whale usually has 55-68 and even 80-90 such stripes. The blue whale is the largest of all cetaceans (and at the same time the largest animal on Earth). The huge size of the blue whale, according to those who have seen it, makes a strong impression. The largest recorded specimen was a female slaughtered by whalers in 1926 near The South Shetland Islands. Its length was 33.58 meters. This whale was not weighed, but its mass, apparently, significantly exceeded 150 tons. Giants with a length of 30 m or more are still rare among blue whales; the average size is slightly smaller — in The Northern hemisphere is 22.8 m for males and 23.5 m for females, and in the Southern Hemisphere it is one meter larger. According to modern research, the large size of whales is associated with the uneven distribution of food in the ocean. A large body volume allows, on the one hand, to absorb a lot of feed when it is in high concentration, and on the other, to survive for a long time in conditions of its shortage. The fat accumulated during intensive feeding allows the whale to go almost without food for several months. The blue whale's eyesight is very poor; it also has a poor sense of smell and, apparently, almost no sense of taste. However, he has excellent hearing and touch skills. The tongue of a blue whale weighs up to 4 tons. The throat of a blue whale is narrow — only about 10 cm in diameter. The heart mass of a large blue whale is approaching a ton, the diameter of the dorsal aorta reaches 40 cm. The skin of the blue whale is quite smooth and even, except for the stripes on the throat and belly. Like all baleen whales, the blue whale has several hundred pairs of baleen plates inside its mouth, consisting of a horny substance (keratin). The length of the whisker plates in a blue whale ranges from 90 cm to a meter, the largest length of the plates is reached in the back rows, closer to the front of the mouth their length gradually decreases to half a meter, the width of the plates is about 50-53 cm.
In general, the blue whale is cosmopolitan. Its historical range covered almost the entire world ocean. In the Indian Ocean, blue whales are found all year round in equatorial waters. In the eastern Pacific Ocean, blue whales begin to occur off the Chilean coast. Blue whales are extremely rare in Russian waters. The population of blue whales in the North Atlantic Ocean is few in comparison with herds in the Southern hemisphere. It is known that blue whales, which spend the summer in the high latitudes of both hemispheres, migrate to warmer areas of low latitudes by winter.
In general, the blue whale shows a tendency to loneliness to a greater extent than all other cetaceans. The blue whale does not form herds, it is mostly a solitary animal, although sometimes blue whales form small groups consisting of 2-3 heads. The blue whale, swimming near the surface of the water, is not nearly as maneuverable as some other large cetaceans. The blue whale dives quite deeply, especially if it is very scared or injured. Data obtained by whalers using special devices mounted on a harpoon showed that a harpooned blue whale can dive up to 500 m. The usual dives of a feeding whale rarely exceed 200 m, and more often they are no deeper than 100 m. Such dives last from 5 to 20 minutes. A grazing whale dives quite slowly — it takes about 8 minutes to dive 140 m and then ascend. After surfacing, the whale's breathing increases to 5-12 times per minute, with a fountain appearing each time. The caudal fin of a diving blue whale is rarely shown — in about 15% of diving cases. Observations of blue whales off the southern coast of California have shown that they spend 94% of their time underwater. At a short distance, the blue whale can swim at speeds up to 37 km / h, and in exceptional cases — 48 km / h, but it cannot maintain such a speed for a long time, because this poses too much stress on the body. At this speed, the whale develops up to 500 horsepower. Grazing bluewalker moves slowly, 2-6 km/h, faster during migrations — up to 33 km/h. The blue whale breathes 1-4 times a minute in a calm state. Studies in the 1970s showed that the breathing rate of blue whales (and tabbies in general) strongly depends on the size and age of the whale. Young whales breathe much more often than adults. The diet of the blue whale is not fundamentally different from the diet of other striped whales. The blue whale is a typical plankton eater, its food composition is dominated by small (no more than 6 cm long) crustaceans from the Euphausiaceae order, forming massive clusters, the so—called krill. A grazing whale swims slowly, opening its mouth and taking in water with a mass of small crustaceans. The stripes on the throat allow the whale's mouth to stretch very much, this is also greatly facilitated by the movable articulation of the bones of the lower jaw. Scooping up the water with the crustaceans, the whale closes its mouth and squeezes the water back through the whalebone with its tongue. In this case, the plankton settles on the fringe of the mustache and is then swallowed. The huge lower jaw, filled with water and food, has such a large mass that it is sometimes difficult for a blue whale to move it to close its mouth. Therefore, it is not uncommon for a blue whale, having gathered food in its mouth, to turn over on its side or even on its back, and then the mouth closes itself under the influence of gravity. Due to its huge size, the blue whale is forced to consume a very large amount of food — according to various sources, the bluewalker eats from 3.6 to 6-8 tons of krill per day, and it is estimated that the number of individual crustaceans in this mass reaches 40 million. The increase in the number of blue whales is the slowest among all baleen whales. Females give birth every two years. This period may sometimes vary depending on the density of the whale population and may have decreased in recent decades. Pregnancy lasts about 11 months
The initial number of blue whales, before the start of their intensive fishing, was estimated at 215 thousand heads. According to other sources, it could be even more, up to 350 thousand. The first bans on blue whale fishing in the Northern Hemisphere date back to 1939; they affected only certain areas. Fishing was completely banned in 1966. According to one data, there are now from 1300 to 2000 bluewales in the entire world ocean, but in this case the number of these whales is even lower than 40 years ago, despite the complete lack of fishing. Other sources give more optimistic figures: 5-10 thousand bluevals in the Southern hemisphere and 3-4 thousand in the Northern Hemisphere. The growth of the blue whale population is slow, but in some places, for example, in areas near Iceland, the increase after the fishing ban reached 5% per year. Due to their gigantic size, blue whales have almost no natural enemies. However, young and sometimes adult individuals can become victims of attacks by killer whales, which, acting together, can tear them apart and eat them. The causes of natural mortality of the blue whale have been studied extremely poorly, even in well-explored areas of the world ocean, such as the North Atlantic. Apparently, there are cases of whales dying under the ice — in the Northern Hemisphere, obviously, in late winter and early spring.
Until the 1860s, the blue whale remained virtually inaccessible to fishermen. Its colossal size and enormous strength made it an extremely dangerous opponent, given that until the end of the XIX century whaling on the high seas was not mechanized and was conducted almost exclusively from boats, using a hand harpoon. In addition, sailing schooners and rowboats could not catch up with the blue whale, and the hand harpoon did not have sufficient killing power. A dead blue whale, unlike smooth whales, usually sinks, so it is impossible to keep it on the surface with the help of boats. The first cases of targeted extraction of blue whales date back to 1868. This is due to the real revolution in whaling, which allowed the mass slaughter of striped whales, which occurred with the invention of the harpoon cannon and the so-called spear grenade. This weapon, the prototype of the 20th century harpoons used until the 1980s, was invented by Sven Foin and was a heavy metal harpoon with a powder charge in the head, fired from a muzzle—loading cannon mounted on the ship. When hit, the charge exploded, which was already enough to reliably defeat the blue whale, after which steel paws opened at the tip of the harpoon and firmly held the weapon in the carcass. Bluewall mining became widespread after The First World War. This was caused by several reasons at once — firstly, the herds of humpback whales were depleted, and it became necessary to find a new source of whale oil and whiskers; secondly, due to technological progress, whale fishing gear has become even more perfect. The peak of production occurred in 1931, when more than 29 thousand heads were scored. The main fishing areas for blue whales were located in the Northern Hemisphere off southeastern Japan, near the Kuril Islands, the eastern part of the Aleutian Ridge and to the south (in the Gulf of Alaska). Bluewalls were mined off the coasts of British Columbia, California, Mexico, and in the Atlantic Ocean — in the waters of Norway, Iceland, Scotland and Ireland and off Newfoundland; to a lesser extent off the west of Greenland, the Faroe Islands and Svalbard and occasionally off the coasts of Spain and Portugal. The last recorded cases of (illegal) blue whale fishing occurred off the Spanish coast in 1978. 45 tons of fat were obtained from one of the largest blue whales captured by Soviet whalers, weighing 150 tons. The meat of the blue whale, like the meat of other baleen whales, is quite edible, unlike the meat of toothed whales, for example, sperm whales, which has a strong unpleasant smell of blubber. The meat of young blue whales is quite soft and tender, pink-red in color. In old whales, it has a dark red color and is tough. Meat concentrate was also prepared from meat, which was a completely acceptable substitute for beef concentrate. Whalebone was very valuable before the widespread introduction of plastics, and a variety of products were made from it. At the end of the 19th century, one of the shops in Boston, specializing in the sale of whaling products, offered an assortment of 53 types of household products made of whalebone (corsets and other parts of women's and men's clothing, brushes, bed springs, etc.).
A blue whale compared to an average adult
A harpoon gun. Her invention made it possible to start mass fishing for striped whales
The skeleton of a Blue whale
People often find the carcasses of dead whales washed ashore. Scientists still do not know the reasons why whales are washed ashore.
The pelican—shaped largemouth is a species of deep-sea ray-finned fish from the suborder sac-like of the order eel-like. Body length according to various sources varies from 60 to 180 cm. The weight is not more than 1 kg. The length of the mouth is about 1/3 of the total length of the body, the rest is a thin, eel—shaped body. Passing into the tail thread, at the end of which the photophore is located. In live fish, it glows pink or red.There are many small curved teeth in the jaws, arranged in several rows. The eyes are small, the anterior and posterior nostrils are in front of the eyes, close to each other. The fish lacks a swim bladder, gill covers, scales, ribs, caudal and ventral fins. The pectoral fins are poorly developed, unlike the dorsal and anal fins, which stretch almost the entire length of the eel-shaped body. There is a bright line or groove on both sides of the dorsal fin with an unknown function. On the edge of the upper jaw, just behind the nostrils, there are tiny eyes, which in the realities of the dark zone of the ocean do not play a significant role in the life of the fish. Nevertheless, fish are able to distinguish the glow from other organisms and identify the silhouettes of small organisms against the background of residual sunlight penetrating to the depth. Navigate at great depths in conditions of pitch darkness and excessive pressure (for a large mouth, this value ranges from 30 to several hundred atmospheres) The fish is helped by the lateral line, which consists of a series of convex tubes instead of holes, as is typical for other fish. The musculature of the fish is poorly developed, which is why the largemouth lacks the small fraction of prey that it manages to catch to provide its body with energy. Mollusks were found in the stomachs of 87 individuals, fish in 37, cephalopods in 15, and shells in 8. Sexual dimorphism is present. Degenerative changes are observed in males after puberty: olfactory organs increase, teeth and jaws decrease. It is believed that reproduction occurs only once in a lifetime. Spermatogenesis in males proceeds synchronously. The gonads have a lobed structure, polycyclic ovaries. Gonads increase during puberty in the abdominal cavity of fish, depress the stomach and intestines, causing their atrophy, and after spawning, the fish most likely dies. They are distributed circum—globally - in temperate and tropical regions of all oceans. They live mainly at depths from 500 to 3000 m (5000m?). Probably, after catching prey, the fish gets rid of water through the gills and swallows it. Since the stomach is not so elastic, the largemouth probably feeds on relatively small organisms.
X-ray of a pelican-shaped largemouth
The deep-sea anglerfish is a suborder of deep-sea ray-finned fish from the order anglerfish.The size is very different from the species living at a shallower depth, they have only a few centimeters. Deep-sea anglers constantly live at great depths, 1500-3000 m, in the thickness of ocean waters. They are characterized by a spherical, laterally flattened body shape and the presence of a "fishing rod" (in females). They are distinguished from other anglerfish by the absence of ventral fins.Traditionally, it is believed that deep-sea fish in appearance are bloated bodies with bulging eyes and ugly shapes. In fact, this is not the case. Deep-sea fish take on the appearance of bloated bodies when they rise to the surface in fishing nets, due to excessive internal pressure, which is 150-300 atmospheres at depths of 1500-3000 meters. Due to the expansion of the walls of the arteries that feed the gland with blood, fish can arbitrarily cause the glow of bacteria that need an influx of oxygen for this, or stop it by narrowing the vessels. Usually, the glow occurs in the form of a series of consecutive flashes, individual for each species. From a depth of about 3,600 m, the luminous "bait" is located in the mouth. Unlike other deep-sea anglers, it hunts, apparently, lying on the bottom. Adult female anglers feed on deep—sea fish, crustaceans and, less often, cephalopods; males - paddlefoot crustaceans and bristle-mandibles. The stomach of females is able to stretch very much, so that they can swallow prey, often exceeding their own size. The voracity of anglers sometimes leads to their own death. Dead anglers were found with swallowed fish more than twice their size. Having captured such a large prey, the anglerfish cannot release it due to the structure of its teeth and chokes.
Some anglerfish families have extremely unusual relationships between the sexes that are not found among other fish and vertebrates. They are expressed in the fact that dwarf males live as parasites on the body of females. Before the transition to parasitism, males have well-developed eyes and large olfactory organs. This allows them to find females by the smell of pheromones, traces of which remain in almost still water of great depths for a long time. Approaching the female, the male apparently visually recognizes her species by the structure of the eka or by the color and frequency of her flashes. Then the male attaches himself to the side of the female with his sharp teeth. Soon he fuses with the female with his lips and tongue, and his jaws, teeth, eyes and intestines are reduced so that eventually he turns into a simple appendage producing sperm. The male's nutrition is carried out at the expense of the female's blood, since their blood vessels also fuse.
The Peacock mantis has a body size from 10 to 35 cm. The grasping legs have an unusual feature: in them the last segment is sharp, serrated, like a blade and is inserted into the longitudinal furrow of the penultimate segment, like a penknife. The first pair of grasping legs is the largest, they grab the prey, and the rest of the grasping legs hold it. It lives in tropical and subtropical seas at depths from 5 to 10 m (occasionally up to 20 m).They lead a predatory lifestyle. Rotopods spend most of their time in burrows. Climbing out, they crawl along the surface of the ground with the help of their hind pectoral legs, as well as dexterous mandibles, which bend at the same time and on which the cancer relies like crutches. Crayfish can swim quite fast.
Among the currently existing animals, mantis crabs have the most complex visual system. If humans have three types of color-sensitive cones in their eyes, then mantis crabs have 16 of them. Moreover, mantis crabs can adjust the sensitivity of their long-wave vision to adapt to the environment. The middle band of the eye consists of six rows of specialized ommatidiums — sockets of photosensitive cells. The four rows contain up to 16 different pigments: 12 of them are color-sensitive, and the rest are used as color filters.
The force of the impact of his claws is comparable to the impact of a .22 caliber bullet! Mantis hits with such power that it literally tears up the water on impact. At the point where the claws click, a so-called cavitation bubble is formed: an area filled with red-hot steam and gas released from the burst water. This bubble bursts instantly, after which a powerful shock wave is formed, which by itself can kill the victim. During the impact, the claw moves underwater at a speed of 72 kilometers per hour, so the hunting throw of mantis crayfish is officially recognized as the fastest among all animals. The secret of such speed and tremendous strength lies in the special structure of the hunting paws of mantis crayfish. These animals use the so-called "latch mechanism": their paws contain a large muscle that contracts for a very long time, and a latch that restrains this very muscle. And at the moment of impact, the latch opens, and the muscle spreads with great speed — it turns out something like a shot from a bow or a crossbow. The secret of their strength lies in the content of the mineral hydroxyapatite, which dampens the force of impact. This mineral is also found in the human body: in teeth and bones.
Killer whales are the largest carnivorous dolphins; they differ from other dolphins in their contrasting black and white color. Male killer whales reach a length of 10 m and have a mass of up to 8 tons, females — up to 8.7 m in length. They have massive teeth, up to 13 cm long, adapted to tearing large prey. The color of the killer whale's body is so contrasting that it seems as if its body has been opened with varnish. The location of black and white spots on the body is never repeated, as well as their size and shape. At the same time, we can safely say that the throat area of killer whales is always white, as is the belly area, along which a white longitudinal stripe of arbitrary shape runs. The average life expectancy of killer whales is 50-60 years, but in good conditions they can live much longer.Killer whales can easily dive to a depth of 300 meters, but they can stay underwater for no more than 4 minutes.
The killer whale is widespread almost everywhere The world Ocean, occurring both near the coast and in open waters, but adheres mainly to the 800 km coastal strip. It is less common in the tropics than in cold and temperate waters. There are no exact data on the total number. The minimum total number is estimated at 50 thousand killer whales
As a rule, killer whales prefer to lead a gregarious lifestyle, forming groups of up to 20 individuals. If the group becomes more numerous, then it is divided into two or more groups. Each group has its own unique set of sounds. Killer whales have a complex social organization, which is inferior in complexity of internal and external social relations only to the social structures of elephants and higher primates. It is based on a matriarchal group (family), usually consisting of a female with cubs of different ages and adult sons.
The killer whale is the top of the food chain in marine wildlife, which has virtually no rivals. Nevertheless, killer whales, as very highly developed marine mammals, have complex tactical and even strategic schemes in use, which are used by flocks for food production. In search of fish, flocks of killer whales usually turn around in a chain and swim at a speed of about 5 km/h. At the same time, echolocation signals allow each animal to determine its position relative to others, stay in contact with them and participate in the general activities of the group. Orcas pin a school of fish to the shore or drive it into a dense ball near the surface of the water, take turns diving into its middle and jamming the fish with tail blows. When hunting seals or penguins swimming on an ice floe, killer whales either dive under the ice floe and hit it, or, lining up in a line, with synchronous movements of powerful tail fins, create a directional high wave that washes prey into the sea. To instill in the cub the ability to easily manage prey on the shore, the mother forcibly pushes the cub into shallow water or even onto land, and watches it from the water if the cub is unable to cope with panic and return to the water on its own. The attack on large whales involves mainly males. They simultaneously pounce on the victim, bite her throat and fins, trying to prevent her from rising to the surface. But when attacking female sperm whales, on the contrary, they try to prevent the victim from going deep (killer whales avoid male sperm whales because their strength is great, and their jaws are capable of inflicting a fatal wound). In addition to whales, killer whales hunt white sharks, which on the one hand are seen as a food competitor, on the other hand they highly appreciate shark liver for the nutritional enzymes contained in it. A female killer whale, using hunting techniques, is able to cope alone with a great white shark, which is not much smaller than herself.
Their commercial extraction was banned in 1982. However, it does not apply to the whaling of indigenous peoples, and to the capture of killer whales for scientific and educational purposes. There are no reliable cases of human death as a result of an attack by a killer whale in the wild, which indicates that they are uninterested in humans as food. Contrary to the idea of killer whales as large and friendly dolphins, they periodically show aggression in captivity. There are individual cases of death of trainers from an attack by killer whales. The killer whales did not attempt to eat the victim whole, bite off a limb from it, chew the victim's torso with their powerful jaws, and the cases of killing people by them can be described as carried out in the least brutal and traumatic way for the dead. This indicates that killer whales are animals with a highly developed psyche, and the reasons for aggression on their part are not limited to a banal search for food, protection of territory and other primitive reasons for attack. Members of packs affected by whaling harbor resentment and can subsequently take it out on boats of equivalent size to the small-tonnage whaling vessels they remember. The experience of studying recorded cases of attacks by foreign researchers indicates that killer whales can attack watercraft, even if they are larger than themselves. At the same time, whalers themselves are not associated in their perception with the ships on which they sail, which suggests that killer whales perceive ships as an independent entity, and not a man-made means of people, and they choose ships, not people, as the object of their revenge. Due to their large size, killer whales are far from the most popular animals in aquariums, today there are about 58 killer whales in captivity around the world. Some of them were born in the wild, others knew nothing but the pool. For many years, discussions have been raging about how humane it is to continue to keep dolphins and killer whales in water parks, but this issue is still very far from being resolved.
The skeleton of a killer whale
The giant hammerhead shark is a species of the genus Sphyrna from the hammerhead shark family. The width of the wings of the "hammer" is 23-27% of the body length. The teeth are triangular with strongly serrated edges, and they have an increasing inclination towards the corners of the mouth. There are 17 rows of teeth in the mouth on each side of the upper jaw. The average length of a giant hammerhead shark is 3.5 m and weighs more than 230 kg. Females are usually larger than males. There is evidence that a hammerhead shark with a length of 7 meters 89 centimeters and a weight of 363 kilograms was caught off the coast of New Zealand. The female, caught off the coast of Florida in 2006, weighed 580 kg with a length of 5.5 m. Such a large weight is explained by the fact that the female was pregnant, there were 55 embryos inside her.
Giant hammerhead fish can be found both in shallow water and at depths up to 80 m. She prefers to stay near coral reefs, as well as on the continental shelf and in lagoons. It makes seasonal migrations.
The giant hammerhead shark is a solitary nomadic predator that, as a rule, shuns other reef sharks. Immature individuals sometimes fall victim to large sharks, for example, a blunt-nosed shark, adults do not have natural enemies in nature. The giant hammerhead shark is an active predator. Its diet is diverse, it includes invertebrates such as crabs, lobsters, squid, octopuses, and bony fish such as tarpon, sardines, sea catfish and small sharks, such as common marten sharks. There are known cases of eating individuals of their own species. The favorite prey of the giant hammerhead shark are stingrays, about 50 sea cats were found in the stomach of one shark. Venomous stingray spikes are often found in the mouths of these sharks, but they do not seem to cause them discomfort; one specimen caught off the coast of Florida had 96 spikes in its mouth. Giant hammerhead sharks mainly hunt at dawn or dusk. We watched giant hammerhead sharks hunting American tailgaters. First, the shark nailed the stingray to the bottom with a powerful blow of the head from above, and then pressed it with its head and bit on both sides, which actually paralyzed the stingray. Then she would take him in her mouth and tear him apart with quick jerks of her head. Like other members of their genus, giant hammerhead sharks are viviparous. Female giant hammerhead sharks can reproduce by parthenogenesis, i.e. without mating with a male. In parthenogenesis, DNA is transmitted to cubs only from the mother. Pregnancy lasts 11 months. The average life expectancy is 20-30 years, and the maximum is 40-50 years.
Due to its large size and large teeth, the giant hammerhead shark is certainly capable of causing fatal injuries to humans. This species has a (perhaps undeservedly) reputation for aggression and is the most dangerous of the hammerhead shark family. In a collision, he may show aggression. Some scuba divers report that giant hammerhead sharks, as a rule, behave timidly, or do not express interest in people. However, there are reports that they swam close to scuba divers and even attacked when diving swimmers into the water. By 2011, there were 34 hammerhead shark attacks on the list, of which 17 were unprovoked and one was fatal. Giant hammerhead sharks are a regular target of commercial and amateur fishing in the tropics, they are caught using longlines, fixed bottom nets, trawls and hooks. Although meat is rarely consumed, their fins are highly prized as an ingredient for soup. Many sharks die in shark nets installed on the beaches of Australia and South Africa. The giant hammerhead shark is extremely sensitive to overfishing due to its small population size and slow reproduction cycle. The International Union for Conservation of Nature has assigned this species the status of "endangered species". Due to intensive fishing, the population of giant hammerhead sharks decreased by 73% from 1978 to 2003.
Photo of the hammerhead shark
