Knowledge about whales

Classification: Education/Science >> Vocational Education

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whale

Whales are mammals that live in the sea. Some whales are very big, and the maximum length can reach 30 meters. Whales are shaped like fish and are spindle-shaped. The head is big, the eyes are small, and the ear shell is completely degraded. The neck is not obvious. The forelimbs are fin-shaped and the hind limbs are completely degenerated; Most species have fins on their backs; The tail is a horizontal fin, which is the main motor organ. Toothed or toothless. One or two nostrils, open at the top of the head. Adults are hairless (many species just have some hair on their mouths). There is a thick layer of fat under the skin, which can keep warm and reduce the proportion of the body. Breathe with your lungs, then inhale on the surface and dive into the water. You can dive 10 ~ 45 minutes. They usually feed on zooplankton, mollusks and fish. Viviparous, usually a calf, is fed with milk. But many people classify them as fish. In fact, they are not fish, but mammals. Distributed in the oceans of the world.

Whales are distributed in all the oceans in the world. It is an aquatic mammal that breathes with its lungs. Its species are divided into two categories: baleen whales, toothless whales, baleen whales and two-nostril whales, such as baleen whales, blue whales, humpback whales and gray whales. Toothed whales have teeth, no baleen whales, only one nostril, such as sperm whales, narwhals, killer whales and so on. Most of the oxygen in the ocean and 60% of the oxygen in the atmosphere are made by phytoplankton. Baleen whales can destroy zooplankton, the number one enemy of phytoplankton. In addition, toothed whales also help to maintain the ecological balance of fish. The toothed whale's food is a large mollusk that feeds on fish. Therefore, without whales in the world, human beings will perish.

We divide whales into two groups:

Toothed whale: Toothed marine behemoths, such as sperm whales, killer whales, dolphins and porpoises.

Baleen whale; Fin whale In fact, these beards are horned teeth that grow in the mouth. They are used to filter water and catch shrimps and other small animals that whales eat. These teeth replace teeth.

Whales are viviparous mammals, not fish. It takes a year for calves to grow up on breast milk. Fish are oviparous vertebrates. Parent fish generally have no habit of taking care of small fish. Whale's "fins" actually evolved from limbs. Fish is not. Whales breathe with their lungs. Fish breathe through gills. Whales are warm-blooded animals, while fish are warm-blooded animals. You can't tell a whale from a fish by whether it has scales or not. Because many fish have no scales.

1. According to the species, baleen whales have two different ways of hunting.

Degreasing type: For example, the beluga whale filters plankton in the process of slow swimming, with its mouth half open and water flowing in from the joint.

Swallowing type: When this whale approaches a big beach of shrimp at the bottom of the sea, it opens its mouth to swallow a lot of water and puts it into a collapsible belly. As soon as the mouth is closed, the whale tongue rolls up the water filtered by the whale's teeth. For example, a blue whale can swallow 25,000 liters of water at a time.

Every year, some whales leave the food-rich polar ocean to find warmer waters to give birth to their offspring. They traveled thousands of kilometers in a certain period of time a few months later. Every winter, many tourists go to Wan Li by boat to meet them in the Hawaiian Sea and the Gulf of Mexico. For sperm whales, males cannot migrate because there are not enough squid in the breeding area.

Whales are mammals that live in water all their lives. They are so dependent on water that they can't live without it. In order to adapt to life in water and reduce resistance, their hind limbs disappear and their forelimbs become paddles. The body becomes streamlined, like a fish. So their diving ability is very strong. Dolphins (small toothed whales) can dive to a depth of 1 00-300m and stay for 4-5 minutes, fin whales can stay underwater at a depth of 300-500m1hour, and sperm whales (the largest toothed whales) can dive below1000m and stay in the water for 2 hours. 1955, a sperm whale was found dead in the sea near Ecuador, and its diving depth reached1133m. A sperm whale strangled by a cable was found at a depth of 2200 meters near Lisbon, Portugal, which is the deepest record of mammal diving so far.

2. Species of whales: As far as the whole marine mammals are concerned, whales have the most species and the largest number. Whales can be divided into two categories: one is called baleen whales, which have no teeth in their mouths and only beards; The other is called toothed whale, which keeps its teeth in its mouth when it is not needed. Although there are not many kinds of baleen whales, they are huge and become the main hunting targets of human beings. There are blue whales with huge bodies, right whales with slow movements and generally large heads, humpback whales with short arms and funny movements, minke whales with small mouthparts and so on. There are many kinds of toothed whales, except sperm whales, the others are generally small, such as killer whales and dolphins. Although the whale's body varies in length and thickness, it is always streamlined and looks like a fish, so people call it a whale. However, whales are animals. It also like people, constantly surfaced to breathe air. Sometimes on the sea, we can see the white fog columns ejected by whales when they exhale, some of which are as high as ten meters, like fountains, which are very spectacular.

Whales all over the world-killer whales.

Black whales are also called killer whales and killer whales. Their English names are killer whales. Because it especially likes the fat of fin whales, Norwegians call them "oil thieves". Black whales are famous for their strong physique and fierce temperament, and are called "tyrants among whales". Strange to say, killer whales are fierce in natural waters, but after being trained in artificial breeding environment, they become very docile and can perform various skills according to people's instructions (such as diving, heading, dancing to music in the water, etc.). ) Since the late 1960s, they have become famous as "Aquarium Stars" in Ocean Parks and Water Hotels. At the same time, specially trained killer whales can also salvage torpedoes and rockets that sink into the seabed according to human instructions.

The most striking thing about killer whales is that they are distributed all over the world, and the cold north and south poles are their tourist attractions. They can not only live in hot water near the equator, but also roam freely in the polar ice sea that is frozen and cold all year round. No matter in the hot equator or in the cold sea water of the North and South poles, their body temperatures remain constant at 36℃. Why? The key is that their bodies have a special device for regulating body temperature-heat exchange system. Black whales rely on this "device" to keep their body temperature constant in the sea at different temperatures.

As we all know, terrestrial mammals rely on the fur on their bodies to keep their body temperature constant. Black whales are mammals that live in the ocean. The speed of heat dissipation in water is 2.5 times that in air, which means that it generates more heat in the body.

Black whales are smooth and hairless, with a thick layer of fat under their skin as a barrier against cold erosion. However, its forelimbs, high dorsal fin and caudal fin have no fat layer, and some vascular networks pass through these parts to form a heat exchange system. These parts are in contact with water and have no fat layer, so they are usually as high as the surrounding water temperature and relatively cold. The blood in killer whales will get cold when they flow through these places. When the blood in these parts leaves the forelimbs, dorsal fins and caudal fins through veins, it will be heated by the heat of arterial blood flowing from the heart to these parts. The advantage of this method is that a lot of heat is transferred back to the body, instead of all the heat being lost to the water through the forelimbs, back and tail.

In a word, the heat exchange system in killer whales can not only prevent the loss of heat in the body, but also spread the excess heat in the body to the surrounding water environment, thus regulating the body temperature and keeping it constant.

Humpback whale:

Alias: Winged Whale, Humpback Whale, Sawarm Whale. The body is large and wide, with tumor-like protrusions along the midline from the breathing hole to the snout and on both sides of the upper and lower whiskers. The dorsal fin is relatively small, which is 2/3 of the length of the back of the body. The flippers are very large, accounting for about 1/3 of the body length, which is the largest among cetaceans, and their front edges have irregular tumor-like protrusions such as serrations. The caudal fin is wide, and the outer edge is also irregular pincer teeth. There are few facial wrinkles, about 14p ~ 35, extending from the lower part to the navel. The back is black with black stripes, the abdomen is black or excellent, and body bags has great individual variation. The white part above the flippers is more than the black part and square white. The ventral surface of caudal fin is white and the edge is black. There are 270 ~ 400 baleen whales on each side, and the baleen whale plate and hair are black and gray.

The average adult body length is male 12.9 meters, female 13.7 meters, and the weight is 25-35 tons. The largest recorded body length is female 18 meters.

Small groups usually travel in pairs. Swimming is slow. When breathing, the fog column is thick and short, which can reach 4 ~ 5 meters. When diving deeply, the huge tail fin is exposed, and the body often jumps out of the water, or a fin limb stands sideways. Go back and forth to the north and south regularly every year. The staple food is small crustaceans and small fish swimming in groups.

The Yellow Sea, East China Sea and South China Sea are distributed in China.

Melon whale:

Alias: tooth melon whale. Morphological characteristics: the head is oval, without snout, the front end is sharp, and the upper jaw does not protrude from the lower jaw. The dorsal fin is located in the middle of the body, wider than the pseudo-killer whale, up to 30 cm high, with backward front edge and blunt end. The length of the flipper is 65438+ 0/6 of the body length, and the end is pointed. The body is dark gray to dark brown, the upper and lower lips are white, and the eyes are black * * *. There is a thick ribbon extending from the head to the dorsal fin along the midline of the back of the body, and it expands into an arc-shaped black * * * shape below the dorsal fin, with white spots in the throat and gray to * * * near the navel. There are 20-25 teeth on both sides of the upper and lower jaws. The body length can reach 2.75 meters and the maximum weight is about 275 kilograms. Newborn whales are about 1 meter long. Tropical species usually swim very fast in groups of tens to hundreds. Sometimes there are cluster tricks aside. Both the South China Sea and Taiwan Province Province are distributed.

Pacific bottlenose dolphin:

Alias: Sickle Dolphin, Sickle Striped Dolphin, Short Nose Dolphin. The snout is short, but the boundary with the forehead is clear. The dorsal fin is tall and eye-catching, with a sickle-shaped back curve and a wide base. The back of the body is black or dark gray, the abdomen is white, the front of the head and the upper jaw are black, the lower jaw is only black at the mouth and nose, and the rest are white. The ventral side of the body is white or grayish white, and the body side is leucorrhea from the lower side of the posterior base to the tail base, and the corner of the mouth is from the front base of the fin. There is a black belt between the bases after crossing the road. The dorsal fin 1/3 is black at the front and gray at the back. The leading edge of the flippers is also black and the trailing edge is gray. The upper and lower caudal fins are black or black-gray. Body color changes greatly. There are 23 ~ 36 teeth in the upper and lower whiskers.

Adults can reach 2.5 meters in length, males are slightly larger than females, and their weight can reach 180 kg. Many of them are large groups of dozens to hundreds of people, which are divided into small groups when eating, and then gathered into large groups when resting or exercising. Sexually active, swimming fast, often jumping out of the water. The body length is about 1.8 meters.

The main prey are small groups of fish and squid.

The East China Sea and the South China Sea are distributed.

Whale is an important member of marine animals. It looks like a fish, commonly known as whale.

There are many kinds of whales, including more than 80 in the world and more than 30 in China. Generally divided into two categories. One kind with a beard and no teeth in its mouth is called baleen whale, with *** 1 1 species; There are more than 70 species of toothed whales. The length of whales varies from 1 meter to more than 30 meters.

Although there are few species of baleen whales, they are all very large, and the smallest known species is more than 6 meters long.

The blue whale is 33 meters long and weighs 190 tons, which is equivalent to the weight of 33 elephants or more than 300 cows. Its tongue weighs 4 tons. Its power is also enormous, 65,438+0,250 kilowatts, and it can tow 588 kilowatts of motorboats, making it the largest animal ever seen on earth. This is the blessing of the sea, only in the sea can it grow so big: First, there is enough food. Although the blue whale is huge, it feeds on krill which is too small to compare with it. This kind of shrimp is rich and easy to catch, which can feed these big bellies. Secondly, the buoyancy of water is very strong, supporting the huge body of the blue whale. The African elephant is the largest animal on land, weighing about 5 tons. If it gains weight, its limbs will not be able to support it, so it can't grow too big. But not in the sea, animals are basically in weightlessness, and no matter how big they are, they can float. But it cannot be increased indefinitely. Beyond a certain limit, the functions of organs such as heart, lung and so on cannot meet the needs.

Humpback whales are skilled in hunting. First, they shoot a string of bubbles upward under water, forming a big circle on the water surface. Bubbles scare krill like air guns and concentrate in the center of the circle. Humpback whales emerge from the center of the circle and swallow them with their mouths open. Because humpback whales have large mouths and high feeding efficiency, each right whale eats 3 ~ 4 tons of krill every day.

Whales are full of treasures. Leather can be used to make leather. Leather shoes, purses and furs made of whale skin are as soft in texture and beautiful in pattern as cowhide. The subcutaneous fat layer of whales is very thick, which can reach ten to dozens of centimeters, and can be used for refining, eating or other chemical raw materials.

A blue whale can produce more than 30 tons of oil, which is equivalent to the total fat of 1 700 pigs or 8 000 sheep. The bones and viscera of whales can be used as medicine or fattening. Whales are priceless. Therefore, many countries in the world, such as Japan and Norway, compete to kill and kill, making many whales on the verge of extinction. The International Whaling Commission had to decide to stop commercial whaling.

The study of "language masters" in the cetacean kingdom shows that killer whales can make 62 different sounds, and different sounds have different meanings. Black whales living in different sea areas and even killer whales of different groups use different "language tones", which are similar to human dialects, so researchers call them "killer whale dialects". Sometimes, a large number of fish appear in a certain sea area, and killer whales come from all directions to feed. But their calls are different from each other. Researchers speculate that killer whales can talk through "language". As for how they understand each other's "dialects", whether they are equipped with translators like humans is still a mystery.