What is a whale?

Whale is an important member of marine animals. It looks like a fish, commonly known as whale. In Er Ya Yi written by Luo Yuan in Song Dynasty, it said, "Whales are big fish in the sea. Its sea swallows boats, and its cave is at the bottom of the sea. Out of the hole, water overflows, which is called whale tide. Or the sunrise is under the tide, and it goes in and out when it enters the tide, so the whale tide sometimes. " Of course, the ebb and flow of tides is a natural phenomenon, and it is not formed by the existence of whales. In ancient times, whales were regarded as the king of fish, saying that "birds have phoenixes and fish have whales". Due to the characteristics of viviparous lactation of whales, people gradually realize that whales belong to mammals. Due to the adaptation to life at sea, many changes have taken place in the body structure and habits of whales. The strong limbs of terrestrial animals have no place in the sea, so the forelimbs of whales become fins, and the hind limbs are of little use, so they are simply abandoned, and a large horizontal tail fin grows on the tail, which is its deep-sea whale.

Main swimming organs. Animal hair plays an important role in resisting cold and keeping body temperature, but it can't keep warm in the sea, but it increases the resistance of swimming, so it gradually disappears. The whole body is smooth and naked, but there is a thick layer of fat under the skin, which keeps the whale's constant body temperature like a warm fat quilt. They roam the coast of Wan Li, dive to the bottom of the sea for thousands of meters and roam freely. From offshore to ocean, from temperate and tropical to polar waters, whales can be found everywhere. Whales have nostrils on their heads, so it is most convenient for them to breathe out of water. Therefore, whales are common across the smoke waves in Wan Li. When they come out for air, they spit out white fog columns, which are as high as several meters to more than ten meters, just like fountains in the sea.

There are many kinds of whales, including more than 80 in the world and more than 30 in China. Generally divided into two categories. There are 1 1 species of baleen whales. 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 species is more than 6 meters long. For example, 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 and has great strength, 1.250 kW. It can tow a 588kW motorboat, which is the largest animal ever seen on the earth. This is the love of the sea, and only in the sea can it grow so big. First, food is abundant. 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. Second, the buoyancy of water supports 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.

Deep sea whale

The huge blue whale is called "the king of beasts". Fin whales are not small, reaching 27 meters long and weighing 95 tons. Humpback whales can sing and dance. They are18m long and weigh 65t. Arctic right whales are short and fat, living in Arctic waters. They are over 18 meters long and weigh 1 14 tons. The gray whales swimming near the shore are also 15 meters long and 16 tons heavy; Although the minke whale is the last of the strong, its body length exceeds 10 meter and its weight is about 5 tons. These are important hunting targets with high economic value.

Most baleen whales feed on zooplankton such as krill. In order to fill their stomachs, they grow special beards in their mouths and filter food from a large amount of seawater, which is one of the most peculiar adaptations among mammals. Must be arranged in two rows on both sides of the palate, each row has 300 ~ 400 whiskers, each of which is a triangular plate, also known as whisker plate. The upper end of the whisker board is wide, the lower end is sharp, the outer edge is smooth, the inner edge is like hair, and the direction of the board is perpendicular to the direction of the head. Seen from the side of the head, the beards are arranged neatly, like a comb, and the distance between two adjacent beards is 0.5 ~ 1.3 cm. When hunting, baleen whales open their huge mouths and swallow krill with seawater. Then as soon as the mouth is closed, the water is filtered out from the whiskers, and the food is filtered on the whiskers and then swallowed. Humpback whales are more skilled at 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. Then humpback whales float out of the center of the circle with their mouths open and swallow them. Whales have big mouths, especially right whales. Its head length accounts for 18 meters of its body length13, its mouth is 6 meters long, and its beard plate is more than 4 meters long, so more than a dozen adults can walk in and out calmly. It is not an exaggeration to call it "the fish that swallowed the boat". Because of its large mouth and high feeding efficiency, each right whale eats 3 ~ 4 tons of krill every day.