Baleen whales and toothed whales. When the ancients named it, even the word whale itself had a fish word. If you write it with the names of mackerel, Spanish mackerel and other fish, it will be more difficult for people to know the true face of Lushan Mountain. Not only Chinese characters, but also foreign countries have similarities. For example, in German, whales are called Walfisch. Until 16 ~ 17 century, whales were regarded as fish and recorded together with fish. In fact, although a whale looks like a fish, it is not a fish, but a mammal, similar to the situation that a bat looks like a bird but not a bird, and it is also a real mammal. Unlike fish, whales are viviparous. Generally speaking, they have a baby every two years. Young babies are fed by their mothers' milk; Fish are oviparous and can lay thousands of eggs at a time. Once hatched, young fish can live independently without breastfeeding. The whale's body temperature is constant, with an average of 35.5℃, which is maintained in cold water and tropical waters. Fish is a temperature-changing animal, and its body temperature changes with the change of environmental temperature. Whales breathe with their lungs. They often need to surface to breathe air. On the other hand, fish can always stay underwater by absorbing oxygen dissolved in water through gills. Whales and fish are similar in appearance because they have lived in the same living environment for a long time, which is a "convergence phenomenon". Although whales belong to mammals, they have been bathed in seawater all their lives and have completely adapted to life in the sea. Whether it is the waters near the Antarctic or the Arctic Ocean, or the equatorial or coastal waters, it can be their active territory and there are traces of them. Although the oceans are vast, they can not only catch food, but also find companions. They are one of the best swimmers in the ocean. When the sea is calm, they can swim leisurely, but when the waves are rough, they still seem to be walking. They can jump out of the water to "watch" the rising red sun in Ran Ran, Ran Ran, or swim thousands of meters underwater to explore the mysteries of the deep sea, carry on with heavy loads and float freely. The Latin name of the "behemoth" whale in the sea comes from the Greek word "sea monster", which shows the ancient people's reverence for this behemoth living in the sea. In fact, the size of whales varies greatly, from a small size of 1 meter to a maximum size of 25 meters. The heaviest can reach about 170 tons, and the lightest is about 2000 kilograms. Most of the physical features live in the ocean, and only a few live in fresh water environment. Their bodies are very similar to fish, streamlined and suitable for swimming, so they are commonly known as whales, but this similarity is only a convergence phenomenon in biological evolution. Cetaceans belong to mammals because they have the characteristics of viviparous, lactation, constant temperature and breathing with lungs, which are completely different from fish. The heartbeat of whales is usually 9 ~ 10 times per minute.

Other species of sickle dolphins, sickle dolphins, and short-nosed dolphins. 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 anus and base 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.

* * * cetaceans are also characterized by constant body temperature, about 35.4℃. Bare skin, no body hair, only a few bristles on the tail, no sweat glands and sebaceous glands. The fat under the skin is very thick, which can keep the body temperature and reduce the proportion of the body in water. The skull is developed, but the skull is smaller, the face is larger, the frontal bone and maxilla are obviously prolonged, forming a long snout. The neck is not obvious, the cervical vertebra is healed, and the head is directly connected with the trunk. The forelimbs are fin-shaped, the toes are not separated, there are no claws, and the elbow and wrist joints cannot move flexibly, which is suitable for swimming in the water. The hind limbs are degenerated, but there are still pelvic and femoral residues, and residual bone fragments can be seen. The tail degenerates into fins, and the skin at the end expands horizontally from left to right, forming a pair of large tail leaves without bone support. The spine gradually tapers in the long and narrow caudal trunk and finally disappears before entering the caudal fin. Unlike fish, the caudal fin can swing up and down and is the main organ for swimming. Some species also have dorsal fins to balance their bodies. Their bones have spongy tissue, and there is more fat in the body cavity, which can increase the volume of the body, reduce the proportion of the body and increase buoyancy. Their eyes are small, without lacrimal glands and transient membranes, and their eyesight is poor. There is no outer ear shell, and the external auditory canal is very thin, but the hearing is very sensitive. It can feel ultrasonic waves, find food by echolocation, contact companions or avoid enemies. There are 1 ~ 2 external nostrils, located on the top of the head, commonly known as spray holes. Generally, the closer the nostril is, the higher the degree of evolution. Breathing with lungs, there is a lung on the left and right, and there are many capillaries in it, which are elastic and can help the circulation of oxygen and adapt to the gas exchange on the water. You need to surface for air every once in a while, and you can also dive for a long time. There are 10 ~ 20 pairs of ribs. The stomach is divided into four chambers. Most kidneys are tumor-like. Male testicles are located in the abdominal cavity. Female animals give birth and breastfeed in water. The uterus has two horns and a pair of breasts, which are located at the cleavage on both sides of the reproductive fissure, and the nipples are slender. Milk is rich in calcium, phosphorus and a lot of fat. Young whales have teeth in the embryonic period, but the teeth of whales are replaced by beards at birth, and the teeth of toothed whales will be preserved for life. Whales are social animals. They usually live in groups in the sea, but when whales breathe, they need to swim to the surface. At this time, the whale breathes through the blowhole on its head, and when it exhales, the water in the air will condense and form the familiar fountain shape. Experts can even tell the species of whales from the height, width and angle of water spray. There are many kinds of whales, which can be roughly divided into toothed whales and baleen whales. There is a very thick layer of fat under the epidermis of whales, commonly known as whale oil. It can keep whales warm and store energy for a rainy day. Because there are many special structures in the whale, it can hold its breath for a long time and slow down its heartbeat, so when it sinks to the bottom of the sea, it takes a long time to surface again. In addition to the oxygen storage structure, when a certain part of the body needs a lot of blood supply, the body will also have a special function of centralized supply. The characteristics of whales The same characteristic of cetaceans is that their body temperature is constant, about 35.4℃. Bare skin, no body hair, only a few bristles on the nose and mouth, no sweat glands and sebaceous glands. The fat under the skin is very thick, which can keep the body temperature and reduce the proportion of the body in water. The skull is developed, but the skull is smaller, the face is larger, the frontal bone and maxilla are obviously prolonged, forming a long snout. The neck is not obvious, the cervical vertebra is healed, and the head is directly connected with the trunk. The forelimbs are fin-shaped, the toes are not separated, there are no claws, and the elbow and wrist joints cannot move flexibly, which is suitable for swimming in the water. The hind limbs are degenerated, but there are still pelvic and femoral residues, and residual bone fragments can be seen. The tail degenerates into fins, and the skin at the end expands horizontally from left to right, forming a pair of large tail leaves without bone support. The spine gradually tapers in the long and narrow caudal trunk and finally disappears before entering the caudal fin. Unlike fish, the caudal fin can swing up and down and is the main organ for swimming. Some species also have dorsal fins to balance their bodies. Their bones have spongy tissue, and there is more fat in the body cavity, which can increase the volume of the body, reduce the proportion of the body and increase buoyancy. Their eyes are small, without lacrimal glands and transient membranes, and their eyesight is poor. There is no outer ear shell, and the external auditory canal is very thin, but the hearing is very sensitive. It can feel ultrasonic waves, find food by echolocation, contact companions or avoid enemies. There are 1 ~ 2 external nostrils, located on the top of the head, commonly known as spray holes. Generally, the closer the nostril is, the higher the degree of evolution. Breathing with lungs, there is a lung on the left and right, and there are many capillaries in it, which are elastic and can help the circulation of oxygen and adapt to the gas exchange on the water. You need to surface for air every once in a while, and you can also dive for a long time. There are 10 ~ 20 pairs of ribs. The stomach is divided into four chambers. Most kidneys are tumor-like. Male testicles are located in the abdominal cavity. Female animals give birth and breastfeed in water. The uterus has two horns and a pair of breasts, which are located at the cleavage on both sides of the reproductive fissure, and the nipples are slender. Milk is rich in calcium, phosphorus and a lot of fat. Young whales have teeth in the embryonic period, but whales' teeth are replaced by beards at birth, and toothed whales' teeth are preserved for life. Whales are mammals that live in water. It has the same physiological characteristics as terrestrial mammals, such as breathing with lungs and viviparous. And has some special physiological structures that have evolved to adapt to the aquatic environment. Whales belong to the animal kingdom, Chordata, Mammalia and Cetacea. The heartbeat of whales is only 9 times per minute, because whales are mammals living in water. They have the same physiological characteristics as land mammals, and they also breathe with their lungs. They can hold their breath in the water for a long time and slow down their heartbeat. This is why we can lurk under the cetaceans in the water for a long time. There are two suborders, namely Blaleenwhales and Odo-ntoceti. The grouping of the two groups mainly depends on their different eating patterns. The main morphological feature of the suborder baleen whales is that they have no teeth, but there are great baleen whales, which can be used to screen plankton, so they are filter-feeding animals. The main feature of Toothed Whale suborder is that it has teeth and is predatory. The number and arrangement of teeth will be different under the influence of predation. There are about 13 families 1 species in the world.