Sharks are not mammals
Although sharks give birth to live young, like mammals, they are fish. In fact, this characteristic causes many people to classify sharks as mammals. Some animals, such as platypuses, are . They do not give birth directly, but are classified as mammals because they feed their young with milk from their mammary glands, which sharks do not have. and dolphins are mammals. But because sharks and whales are so similar, many people tend to believe that they are also mammals.
What characteristics of sharks distinguish them from mammals?
Sharks are cold-blooded, or ectothermic, animals. This means that sharks' body temperatures are regulated by conditions. Mammals are warm-blooded animals. Their temperature remains constant despite fluctuations in environmental conditions. Warm-blooded animals, also commonly called endotherms, have adaptations that help them maintain a constant body temperature. These adaptations include shivering and a protective coat.
Also, as stated earlier, mammals feed their young with milk from their mammary glands, but sharks do not. Mammals have fur on the surface of their skin. Sharks have scales that help them swim. Whales, which many associate with sharks, have fur on the surface of their skin, but it is almost invisible. It should also be noted that mammals breathe through their lungs, while fish use gills.
Conclusion
Sharks are not mammals, they are a superorder of fish. They give birth to live young, but this alone does not give them the opportunity to become a mammal. They do resemble whales, however, this does not allow them to be classified as mammals. Sharks are fish because they lack some of the basic characteristics of mammals, but they have most of the characteristics of fish.
Any sea traveler knows that meeting dolphins on the way is good luck. The plausibility of this concept, or even of some kind of superstition, is impossible to verify. However, one can argue with the fact that the jamb of these sea beauties, seeing off the ship, charges with a wonderful mood and gives those who see it with their own eyes an unforgettable experience and emotional uplift, it simply does not make sense. The intelligence of dolphins is legendary.
Scientists claim that they are able to communicate with their own kind, being at a distance of tens and even hundreds of kilometers from each other. Moreover, this is not just a roll call or a kind of communication - it can be warnings of danger, that is, a kind of manifestation of concern for fellow humans. Based on this knowledge, and many other facts concerning the intellectual inhabitants of the seas and oceans, many people are interested in a completely logical question: is a dolphin an animal or a fish? In today’s article we will try to clarify this dilemma, and also tell you along the way about the inhabitant of the water element and interesting facts about him.
If the ancestor is a predatory animal, will the intelligence of the descendants match them?
To begin with, I would like to clarify the situation regarding the fact that humans do not associate fish with highly developed creatures capable of understanding the speech of homo sapiens and learning certain commands, for example, like dogs or cats. People are accustomed to believing that only animals are capable of learning, taming and are not averse to contact with humans. But fish are unlikely to display similar behavior due to the fact that they lack such instincts. It is known that dolphins seek communication not only with their own kind, but also with humans. This is why many people cannot understand whether a dolphin is a fish or an animal.
In some water parks you can attend performances where, for example, a beluga whale or the hero of our today’s article will play ball with the presenter, and perhaps even draw pictures, holding a brush or a special felt-tip pen in its beak. Again, such performances most often involve fish belonging to the order of mammals and cetaceans, the ancestors of which were sea otters - predators living in the water. And the dolphin, as you know, belongs specifically to the cetacean family. Therefore, certain questions arise:
- Is a dolphin an animal or a fish?
- Was predator intelligence transferred to cetaceans over the entire period of evolution?
Interest caused by intelligence
First of all, it should be noted that there are a sufficient number of species of mammals, more precisely, dolphins, in nature. This number equates to 40. They are considered representatives of toothed whales and belong to the cetacean family. Due to the fact that dolphins are the ancient inhabitants of the planet, as well as because of their contact and desire to communicate with people, humanity, and especially scientists, showed concern for these inhabitants depths of the sea extreme interest. This state of affairs is also due to the fact that dolphins are considered intelligent and understanding creatures. It has been proven that every individual at birth receives given name, which he subsequently uses when meeting other relatives. Another interesting thing is that the sounds made to communicate with each other have ancient inhabitants marine flora there are about 14 thousand. By the way, many cannot decide the answer to the question “are dolphins animals or fish?” only because mammals live in water.
Description of a creature that many consider a symbol of friendship
Naturally, the appearance of dolphins is quite unusual for marine inhabitants, since there are no scales on the body. Such a streamlined structure, devoid of the main thing distinctive feature fish, puzzles many people, and they are at a loss: is a dolphin a fish? Or is it an animal?
The photos presented in the article once again confirm the fact that the dolphin has no scales. It is thanks to this quality that mammals adapt to both great depth, and to sliding on the surface of the water. They are capable of reaching speeds of 40 km/h. Their body length is about 1.7 meters and their weight is adult can reach an average of 150 kg. The head is oblong in shape with a pronounced beak. An interesting thing is that dolphins are excellent at navigating depths because they have good eyesight. They are capable of jumping out of the water more than 9 meters. The record holder for weight is the white-faced dolphin, whose weight reaches 300 kg and whose body length can reach up to 3 meters. When figuring out whether the white-beaked dolphin is a fish or an animal, what answer should you expect? It would be fair to assume that this creature, like its other relatives, belongs to the class of mammals.
Is a dolphin an animal or a fish?
To the most basic distinctive features creatures living in the vast seas and oceans that can help answer main question articles include:
- Dolphins are flexible, muscular and quite nimble mammals. This feature is due to the fact that they have an extraordinary fin on the bottom and in the back area.
- The heads of these creatures are medium in size, pointed, which allows you to see the transitions from the frontal to nasal parts. This structure of the skull is very similar to the structure of the head in animals.
- Dolphins have teeth, about sixty of them.
- Dolphins are endowed, like all fish, with excellent vision. By the way, some animals may not have keen eyes, but they will have an excellent sense of smell, which in turn allows them to hunt unhindered.
Features of skin and coloring?
The coloring of dolphins can be either one-color or two-color, depending on the species. Because of special structure skin The mammal constantly sheds, but this condition does not cause them any discomfort. By the way, availability natural process Molting also makes it difficult for many to determine whether a dolphin is a fish or an animal. As for color, probably the predominant grey colour- this is a kind of camouflage of a mammal from predatory fish and the dangers that lurk.
Intelligent beings
Every inquisitive adult or child has the question “is a dolphin a fish, or is this mammal an animal?” can also cause difficulties because these creatures are endowed with intelligence. It is known that they are able to save people, show lost ships and boats the right path, can learn commands and even draw. Scientists have proven that, along with humans, dolphins are capable of showing emotions: empathy, suffering, sympathy. By the way, the fact that they communicate and talk through various sounds also speaks volumes. Well, for example, that loneliness is alien to them.
Mammalian diet and hunting ritual
Dolphins hunt in schools, using their main weapon - echolocation, which helps scan the water for the presence of fish. In cases where a school of mammals detects a potential prey, they enormous speed approach her and make sound signal, leading the victim into a state of panic. By the way, the main diet of dolphins is fish or animals (similar to themselves, but small), because the heroes of this material are carnivores. They give the greatest preference to shrimp, squid, jellyfish, octopus and even birds.
Features of reproduction
Mating in mammals takes place in motion, as, in fact, the birth of a new inhabitant of the waters. Each newborn dolphin is sufficiently developed, which allows it to immediately follow the pod. Dolphins teach their young to hunt and communicate, which ultimately leads to independent living. By the way, along with some animals, dolphins are capable of experiencing pleasure from sex. This phenomenon also provokes a question that requires an answer: is a dolphin a fish or an animal?
Enemies of dolphins
Like any other mammals, dolphins also have dangerous enemies. They are sharks and even their closest relatives - killer whales. Although, probably, man himself can be called the worst enemy of dolphins, since for poachers mammals are an excellent source of meat and a profitable trade.
Dolphins are one of the most mysterious animals on our planet. The intelligence of these sea inhabitants considered so high that they are called “people of the sea.” Scientists say that dolphins are smarter and smarter than all other animals.
Dolphins live in water, but they are not fish, but mammals from the order Cetacea. That is, they need air - they breathe with their lungs, not their gills. People can always see dolphins' faces on the surface of the sea because dolphins can stay underwater for an average of about 3-5 minutes (although dolphins have been recorded underwater for 10 to 15 minutes). Dolphins feed their young with milk.
Dolphins are found in many seas and oceans of the world, including the Black Sea.
Dolphins live up to 75 years, most often about 50, in captivity usually about 30. With the help of its 88 teeth, the Black Sea dolphin eats about 30 kg of fish per day, the mass of dolphins is up to 500 kg. The body temperature of a dolphin is the same as that of a person - 36.6 degrees. The gestation period of dolphins is about 12 months. The female dolphin usually brings one calf 50-60 cm long and carefully guards it for some time.
When you mention a dolphin, you are more likely to think of the species Bottlenose Dolphin (Tursiops truncatus). Bottlenose dolphins owe their popularity partly to numerous references in cinema and fiction and high learning ability.
The skin of dolphins is a miracle of nature; they are able to dampen the turbulence of water near the surface of a fast-swimming body, which reduces the speed of movement - designers learned from dolphins submarines, creating artificial skins for submarines. And the feeling of dolphin skin to the touch is completely unusual, and also brings joy: it looks dense, like it’s made of plastic, but when you run your palm over it, it’s tender and soft, it seems like thin silk.
When dolphins began to be studied and trained in the middle of the last century, the first results of this work seemed so unusual, and even surprising (they talked about it a lot, wrote and made films) that gradually a legend about the unusual high intelligence dolphins; one could often hear that they were no more stupid than a person, only their minds were different.
The brain of an adult dolphin weighs about 1,700 grams, while that of a human weighs 1,400. A dolphin has twice as many convolutions in the cerebral cortex. At the same time, there are relatively few neurons per cubic millimeter of its substance (less than in the brain of primates).
The results of studies on the behavior and physiology of the brain of dolphins are very contradictory. Some put their ability to learn at about the level of a dog and show that dolphins are very far from chimpanzees. Research on the communication methods of dolphins, on the contrary, leads to the conclusion that we have not yet come close to understanding this form of life in natural conditions and comparing the level of intelligence of dolphins and chimpanzees is simply incorrect. One property of the dolphin brain is completely unique: it never really sleeps. They sleep - alternately - then left, then right hemisphere brain The dolphin needs to come to the surface from time to time to breathe. At night, the waking halves of the brain are responsible for this, in turn.
The language of dolphins can be divided into 2 groups: Body language (body language) - various poses, jumps, turns, various ways swimming, signs given by the tail, head, fins.
The language of sounds (language itself) is a sound signaling expressed in the form of sound impulses and ultrasound. Examples of such sounds include: chirping, buzzing, squealing, grinding, clicking, smacking, squeaking, popping, squeaking, roaring, screaming, screaming, croaking, and whistling.
The most expressive are whistles, of which dolphins have 32 species. Each of them can denote a specific phrase (signals of pain, anxiety, greetings and a calling cry “come to me,” etc.). Scientists studied dolphin whistles using the Zipf method and obtained the same slope coefficient as that of human languages, that is, they carry information. IN Lately About 180 communication signs have been discovered in dolphins, which they are trying to systematize by compiling a dictionary of communication between these mammals. However, despite numerous studies, it has not been possible to completely decipher the language of dolphins.
Each dolphin has its own name, to which it responds when its relatives address it. This conclusion was reached by American scientists, the results of which were published in the journal National Academy Sciences USA (PNAS). Moreover, experts who conducted their experiments in the American state of Florida found that the name is given to the dolphin at birth and is a characteristic whistle.
Scientists captured 14 light gray bottlenose dolphins in the wild and recorded the various sounds these mammals made as they communicated with each other. Then, using a computer, “names” were extracted from the records. When the name was “played” for the flock, a specific individual responded to it. The dolphin’s “name” is a characteristic whistle, the average duration of which is 0.9 seconds.
Everyone has heard that sometimes dolphins and other whales wash ashore. Sometimes this happens due to illness, poisoning or injury. There is another hypothesis that explains the reason for this strange behavior dolphins: it turns out that with a certain shape of the coast, composed of certain types of sediments, among the cacophony of sounds generated by the surf, sometimes a sound arises that exactly corresponds to the cry of a dolphin for help. Animals, hearing these sounds, instinctively rush to help - and end up on the shore.
Dolphins eat fish. A lot of fish: each member of the flock should eat 10-30 kilograms per day. Dolphins are warm-blooded; they need to maintain a high body temperature, sometimes very cold water. The subcutaneous layer of fat also helps with this - it acts as a heat insulator and source of energy for the intracellular oven: burning fats and carbohydrates with the release of thermal energy. Fuel reserves need to be replenished all the time, so they constantly hunt. They catch up with a school of fish - no one in the sea swims faster than them - and surround it. If this happens very close to the shore, the dolphins form a semi-ring and press the fish to the beach; compressing their hunting formation, they push the fish into the shallowest water and eat it there - while they swim into the very waves of the surf, so shallow that their dorsal fins stick out of the water, and their pectoral fins touch the sand at the bottom.
Having surrounded a school of fish further out into the sea, the dolphins do not rush, each individually, after the prey, but organize the school in a ring, preventing the fish from scattering, and one by one plunge into the school. Having caught prey, they return to their place in the pen.
Where there are fish, there are dolphins. U Black Sea coast the fish are most abundant in spring and autumn - when schools of mullet and anchovy go to the Sea of Azov for summer feeding, or return to winter in the Black Sea - along the coast of the Caucasus. Therefore, dolphins most often appear here in April-May and September-October. And in the Kerch Strait itself - the gate Sea of Azov– hundreds of dolphins stand at the outpost, meeting migrating fish stocks.
In summer, bottlenose dolphins also often come straight to the beach - they are more often seen in the early morning or afternoon - perhaps because there are fewer swimmers at this time.
Dolphins live in schools, in which everyone is relative, which is why their mutual assistance is so well developed. They always help a weakened dolphin stay near the surface so that it does not choke; There are stories of how dolphins came to the aid of drowning people. They never act hostile. Dolphins learn tricks very quickly - they only need one correct execution of an exercise on a signal, for which they are rewarded with a fish, so that the skill is fixed in memory. True, they also easily forget their skills if the coach forgets to reinforce a useful habit.
Dolphins live for about 30 years. Dolphins are born approximately once every two years. At this time, the dolphin tries to jump high so that the calf can take its first breath. Dolphins are very touching parents, caring for their young for about five years. And even when reaching puberty, the cub still remains strongly attached to its mother and tries to follow her everywhere.
For a long time, scientists were puzzled by the question of how dolphins sleep. After all, in the sea you can easily drown or become a victim of attack by other predators. However, it has now turned out that the sleep of dolphins is not similar to the sleep of ordinary animals - during sleep, one hemisphere of the dolphin rests, and the other is awake. Thus, the dolphin is always in control of the situation and, at the same time, gets complete rest.
Definitely, something makes us treat dolphins differently than other animals - “friends of man”... Friendly, cheerful, cute... They are really friendly and curious: they are not afraid to swim up and play with a person, although more often - or not pay attention to people, or simply swim away - they have their own worries at sea. Maybe it's the dolphin's smile? After all, they always smile - for some reason, that’s how their face is structured (I don’t even want to call it a muzzle!). And this smile with big eyes- one of those smiles that make us involuntarily smile back - not all people know how to smile like that.
Almost all species of dolphins live in warm salty waters. There are 47 of them in total. These are the indigenous inhabitants of the seas and oceans. But besides marine mammals, there are also river dolphins, representing a separate family, which includes 6 species. These animals live in the rivers of India, China and South America. Their habitat is the Ganges, Indus and Brahmaputra in India. In China they can be found in Lake Dongting, and in South America they chose the Amazon, Orinoco and La Plata for themselves.
River dolphins inferior in size and weight to their own sea relatives and have a more primitive brain structure. The body length of these animals usually ranges from 1.5 to 2.5 meters, and the weight is never less than 40 kg, but does not exceed 120 kg. The bodies of river animals are usually brown or almost White color, sometimes it’s true that you come across dark ink. The vision of these mammals is very weak or almost completely absent. The same thing characteristic difference from their marine counterparts - these are cervical vertebrae. They are not fused into a single bone like those of ocean inhabitants, but are divided just like those of land mammals.
Dolphins for the most part are heat-loving animals. Only people love cool waters individual species. These include striped dolphin. It is common in the northern part Pacific Ocean. It can be found off the coast of Sakhalin and the Kuril Islands, in the waters adjacent to California and Japan. This mammal reaches a length of 2.2-2.3 meters. Average weight is 140 kg. The maximum weight of males can vary between 180 kg. Females are never lighter than 100 kg.
This is a very lively, fast and energetic dolphin. It can often be seen from the sides of ships. Swift, graceful bodies with dark narrow stripes on the sides can accompany the ship for a very long time. Moreover, the animals not only swim in a parallel course, but also easily overtake the floating craft, cross its path and make various jumps and pirouettes.
The striped dolphin's closest relative is common dolphin. Along with the shores of Canada, England, Korea and Japan, it also loves the warm waters of the Mediterranean and Black Seas. It can also be found off the coast of Australia, where the animal feels quite comfortable. The dolphin is very graceful and the fastest of all its sea counterparts. In water it easily reaches speeds of 60-70 km/h. Loves to jump. Their height reaches 5 meters.
The color of the squirrel is very beautiful. The back is black with a greenish tint, and the belly is white. The eyes are surrounded by black circles. The dolphin reaches a maximum length of 2.4 meters with an average length of 2 meters. The weight of the animal is about 110 kg. The common dolphin has a high dorsal: its height is 80 cm. These mammals live in large flocks and love to frolic near the water surface.
Dolphin species would have lost a lot if there had not been such a representative among them as bottlenose dolphin. This is a large mammal, reaching a length of 2.3-3.2 meters. Sometimes bottlenose dolphins are found more impressive size with a body length of 3.6 meters. The mass of this dolphin is usually within 300 kg. The maximum weight reaches 400 kg. The habitat of this animal extends to all temperate and warm waters World ocean. Bottlenose dolphins can be found in Cherny and Mediterranean seas, V Indian Ocean, in the Atlantic and in the Pacific, where he really loves the waters washing the shores South-East Asia and Australia.
The body color of different individuals is not the same, but varies in shade. Mostly dark brown back and gray belly predominate. There are animals with white bellies. Sometimes you can find a representative of the species whose entire body is a uniform gray color. The speed that a bottlenose dolphin develops in water is 40 km/h. He developed a very good and friendly relationship with the person. The dolphin is highly trainable and even learns some words spoken by people. This species performs in dolphinariums more often than any other, impressing spectators with its skill.
All species of dolphins, without exception, have one characteristic feature. Sometimes they're in mass quantity wash ashore and die. Specialists this phenomenon explained differently. The prevailing point of view is that such suicides are the result of the work of certain brain centers of the animal, directly related to the generation of high-frequency sounds. Sometimes the established oscillation frequency earth's surface resonates as a result of the influence of external oscillatory sources on it. These can be wind, tremors earth's crust or the operation of ship radars.
The modified frequency signal may match the sound made by a wounded dolphin. It’s like a person to whom sometimes the howling of a storm outside the window seems like the cry of a child. Let us remember A.S. Pushkin: “Then she will howl like a beast, then she will cry like a child.” A nearby flock perceives such a signal as a call for help. She quickly rushes to the coast, washes ashore and dies. Similar actions are observed in all marine mammals that do not abandon their fellows in trouble (for example, in the same whales), which once again confirms the correctness of this version.
Dolphins are marine mammals animals that belong to the suborder of toothed whales. They are found in seas and oceans, as well as rivers that have access to the sea. As a rule, they feed on crustaceans, mollusks, fish, and some do not disdain sea turtles and birds.
There are more than thirty species of dolphins in the world, the most common of which are: killer whales (Orcinus orca), ball-headed dolphins (pilot whales - Globicephala), gray dolphins (Grampus griseus), Chinese lake dolphins (Lipotes vexillifer), common dolphins (Delphinus delphis) , bottlenose dolphins (Tursiops), and others. Dolphins can't for a long time be under water, so they periodically float to the surface for air. Males are usually larger than females, they can be easily distinguished from each other by their fin - the male has a higher dorsal fin.
The gestation period of dolphins, depending on the specific species, lasts from 12 to 16 months. Basically, only one cub is always born, which stays next to its mother until about two years of age and feeds on her milk. The average lifespan of dolphins is 20-25 years, but there are cases where some individuals lived up to 50 years.
There are quite a few legends about dolphins, filmed feature films and books have been written. Among other things, there are quite a few myths regarding these animals. Let's look at some of them.
Dolphins save drowning people. Perhaps this is true. But scientists are quite skeptical about this statement. They are more inclined to believe that these animals simply love to play, pushing objects with their noses. Also, they have a natural reflex associated with the birth of a baby: the pod unanimously “pushes” a newborn baby dolphin to the surface so that it can breathe air. In addition, the animal must, firstly, realize that the person is actually drowning, and secondly, figure out how to save him.
This is a very smart animal. There have been, are, and probably always will be heated debates among scientists on this subject. Some believe that dolphins, in their own way, mental development superior to man. Others argue that the mental abilities of these mammals can only be compared with dogs and chimpanzees. In general, opinions are divided, but “ordinary” people (not scientists) who ever come into contact with these animals say that dolphins understand everything, they just cannot say.
Dolphins don't hear anything. These animals have an inner ear, thanks to which they hear perfectly under water. In addition, their hearing is very acute and they tend to hear sounds in the range from 16 hertz to 280 kilohertz. While in humans the hearing threshold does not exceed 20 kilohertz.
Dolphins have good eyesight. This cannot be said about some species of dolphins. For example, the Susu dolphin, which lives in the Indus River of Pakistan, is blind. And why does he need vision if the water in this river is muddy and it is impossible to see anything in it? How does he even live then? Thanks to natural sonar, that is, echolocator. With the help of this “device,” dolphins seem to “feel” everything that surrounds them and can accurately determine the location of this or that object.
Dolphins help fishermen catch fish. It is well known that friendly relations usually develop between humans and dolphins. And people involved in fishing “use” this friendship “wisely.” For example, several fishermen enter the sea and begin to tread water with sticks. Dolphins, attracted by this noise, swim in a school to the shore, thereby “pushing” schools of fish in front of them. Thus, the fish get caught in fishing nets, and the dolphins swim back to the sea, but return again as soon as they hear a familiar noise.
Dolphins can always recognize a specific person. This is not an entirely true statement. If a dolphin meets a person on land, he will not recognize the same person in the water. And vice versa, having met a person in the water, a dolphin does not recognize him on land. That's how they are built.
Dolphins do not understand human speech. It would be more correct to say that they cannot hear human speech well. This is due to the fact that dolphins are, as it were, “tuned” to their own wave (frequency), on which they communicate with each other. Therefore, in dolphinariums they use a whistle instead of a voice - it is more understandable for dolphins. But they hear and even feel music perfectly. Also, these animals understand hand movements and facial expressions well.
These mammals are able to cure a person from all diseases. This is not entirely true. For example, a paralyzed person after dolphin therapy will still not be able to live a full life, but his mental (moral) state will improve significantly. Most often, dolphins manage to cure people who have various nervous diseases or deep depression. How they do this is still unknown. Scientists believe that the whole point is in the special ultrasonic radiation that comes from the animal. When a dolphin communicates with healthy person, then it makes a calm clicking sound; if the animal senses that the person is sick, it begins to rumble. After such “sessions” the dolphin gets very tired and tries to be alone to gain strength. Therefore, dolphin therapy is in increasing “demand”, and this is not a made-up fact.
Dolphins are used in military service. Yes this is true. These animals were especially often used during hostilities. Dolphins acted both as scouts and even as killers. Now they mainly act as guards of maritime borders.
Dolphins are very aggressive creatures. It's too strong a word. Of course, we should not forget that a dolphin is an animal, and all animals have aggressive behavior, especially during the period of sexual desire. It’s better not to get in the way of dolphins in love - their aggressiveness will manifest itself in full! Also, if the dolphin thinks that communicating with specific person he is tired - he can also show his dissatisfaction. In other cases, they are quite sociable and peaceful animals.
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