Whales swim freely in the Sea of Wan Li and float freely in the deep sea of 1000 meters. Look at it, it's almost like a fish. It has fins, a tail and a streamlined body. Once out of water, it will die. Actually, whales are not fish at all, but viviparous mammals. Their ancestors first lived on land. 50 million years ago, whales were forced to leave the land and go deep into the sea because of the sudden cooling of the earth's climate. After living in water for a long time, the appearance of their bodies has changed to adapt to life in water, the outer ear shell has degenerated, the forelimbs have become swimming fins, the hind limbs have completely disappeared, the protruding breasts have moved into deep cleavage, and the male whale's external genitals have also moved in. However, it still retains the lungs that live on land. It can't breathe in water like a fish, and it must float to the surface to breathe air regularly. When breathing, the jet of water is ejected from the nose of the head, as high as 10 meter, which is very spectacular like a fountain in the park.

Whales are also good singers in the sea. An American zoologist, after more than 10 years of research, found that whales can sing beautiful songs and sound like euphemistic birds. Whales rely on these songs to convey information, coordinate collective actions, avoid obstacles and contact their companions.

Whales have many uses. Whale meat is edible. Whale oil is an excellent tonic and can also be used for lighting. It is also a high-quality raw material for industrial products such as human cream and soap. Whale skin can be used for tanning, whale bone can be used as feed and fertilizer, whale liver can be used as medicine, whale intestine is the best surgical line, and whale is also a high-quality raw material for making perfume. Whale wings are a delicacy at the banquet, and even whale teeth and beards can be made into craft decorations.

Whales at sea are a big family. Existing whales can be divided into two types according to whether they have teeth: one is toothed whales with sharp teeth, such as killer whales and dolphins swimming in groups, and sperm whales with huge heads. The other, known as the minke whale, has no teeth in its mouth but a beard, including the blue whale with a big body and the minke whale with a small nose.

(1) The giant among whales-the blue whale. The blue whale is a veritable "giant in the sea", with a maximum length of 33 meters and a weight of 190 tons. Its tongue weighs 3 tons, and its heart alone weighs 700 kilograms. Compared with whales, the largest African elephant on land is just a drop in the ocean.

Such a huge animal likes to eat tiny zooplankton, especially krill which is only six or seven centimeters long. Blue whales can eat one ton of krill a meal and four or five tons a day. In summer, blue whales travel long distances to the Southern Ocean or the Arctic Ocean, where there are plenty of krill. In winter, they will return to warm waters to mate and have children. Therefore, in the northern Yellow Sea and Bohai Bay of China, there are more blue whales in winter and spring.

The blue whale is a unique Hercules in the animal kingdom. The power of a whale can reach 1700 horsepower, which is comparable to a locomotive. It can tow 800 horsepower motorboats. The blue whale is not only big and powerful, but also swims very fast. It can swim 27 kilometers per hour and even accelerate to 37 kilometers in a short time of 10 minutes. However, such a huge sea animal has no self-defense weapons, only scary. Instead, it is often bullied by killer whales younger than it, and even eaten alive.

(2) ferocious sperm whales. The largest sperm whale is 20 meters long and weighs 60 tons, ranking first among toothed whales. Its head is heavy and its tail is light, just like a giant tadpole. Its huge head accounts for about one-third of its body length. Its big head floats on the water by a large amount of whale brain oil in the bone cavity of the head. Although the head is big, the jaw is small and narrow. The upper jaw has teeth more than 20 cm long, but the lower jaw doesn't. Sperm whales have an unusually fierce habit. They specialize in catching 30-meter or 40-meter-long king squid at the bottom of the deep sea. Once bitten by it, it's hard to get rid of it. After several hours of life-and-death struggle, the king squid is often buried in the belly of sperm whales.

Among all whales, the sperm whale dives the deepest, reaching 2200 meters, which is called the diving champion. Fierce sperm whales usually like to play, but also can float on the sea for a long time and sleep soundly. Sperm whales hear the sound of whaling guns, and groups of sperm whales put their heads together in a chrysanthemum shape, with their tail fins facing outward and flapping on the water. It doesn't know that this is a good opportunity for whalers.

Sperm whale brain oil is a very useful lubricating oil, which is indispensable for many precision instruments such as watches and rockets. The famous Long Xianxiang is a foreign body in its intestine, which is an extremely precious fragrance retention agent, hence the name of the sperm whale.

(3) ferocious killer whales. A large number of facts show that killer whales are cruel and gluttonous, and they are evil wolves among whales. Someone once found 13 dolphins and 14 seals in the stomach of killer whales. Black whales are brave and cunning. They can play dead to trap seabirds, seals and other animals. When they attack baleen whales, dozens of killer whales often act together, biting their heads with their big mouths and whipping them with their tail fins until the baleen whales stick out their tongues, and the killer whales rush to tear their lips and tongues, and then eat their heads and leave after a full meal. When fishing, they use another clever strategy. First, some killer whales form a big circle and trap the fish in it. Then the killer whales take turns rushing into the fish pile to choose fat and swallow it. After eating all the fish, they swam away quickly.

(4) smart dolphins. Dolphin is a clever whale. There were all kinds of magical legends a long time ago. /kloc-More than 0/00 years ago, on the coast of New Zealand, there was a white dolphin, which led the seagoing ship through the dense fog, bypassed the thrilling reef and successfully reached a safe place. For more than 20 years, this white dolphin has been a volunteer pilot. Under its guidance, no ship has touched a reef. More than 20 years ago, a dolphin pushed a woman who fell unconscious and pushed her to the beach.

Trained dolphins can perform many programs. He can play table tennis, dance, catch and shoot, and like an acrobatic troupe actor, he can perform actions such as drilling fire rings and ringing bells. The U.S. Navy trained dolphins as underwater scouts, let them spy on ships coming and going, train them to clear mines and launch underwater missiles! More specifically, a dolphin trained by a psychology professor in the United States quickly mastered the word 12 and understood simple sentences of people, such as "get the ball, ring the bell and come again".

Why are dolphins so smart? It turns out that its brain is not only big, but also has many grooves. According to the measurement, the ratio of brain weight to body weight of dolphins is 1. 17%, while that of humans is 2. 1%, and that of orangutans is only 0.7%. The width of its brain exceeds its length, which makes it particularly sensitive to sound. In addition, the dolphin brain has a unique ability. During sleep, the two hemispheres of the brain can work and rest in turn, once every ten minutes, which makes dolphins struggle with the wind and waves all day without fatigue.