Baleen and toothed whales. When the ancients named it, even the word "whale" itself had a radical "fish". If it was written together with fish names such as mackerel and mackerel, it would make it even more difficult for people to recognize the true face of Mount Lushan. This is not only true for Chinese characters, there are also similarities abroad. For example, in German, whales are called giant fish (walfisch). Until the 16th and 17th centuries, some natural science books treated whales as fish and recorded them together with fish. In fact, although whales look like fish, they are not fish, but a type of mammal. This is similar to the situation where bats look like birds but are not birds, but are also a type of real mammals. Whales are different from fish in that they are viviparous, usually giving birth to one calf per litter, and the young are fed and grown up by the mother's milk; while fish are oviparous and can lay thousands of eggs at a time. Once the young fish hatch, You can live independently without breastfeeding. The body temperature of whales is constant, with an average of 35.5°C, and this body temperature is maintained whether in cold waters or tropical sea areas; fish are cold-blooded animals, and their body temperatures change with changes in environmental temperature. Whales breathe with their lungs and need to surface frequently to breathe. Fish use their gills to absorb oxygen dissolved in the water, allowing them to stay underwater. The similarity in appearance between whales and fish is caused by them living in the same living environment for a long time, which is a "convergence phenomenon." Although whales are mammals, they bathe in the sea throughout their lives and are completely adapted to life in the sea. Whether it is the waters near the Antarctic or the Arctic Ocean, whether it is the equatorial waters or coastal sea areas, they can be found in their activity areas. Although the ocean is vast and vast, they can both catch food and find companions. They are one of the best swimmers in the ocean. When the sea is calm, they can swim leisurely, and when the waves are rough, they can still take a leisurely stroll. They can jump out of the water to "look at" the rising red sun, and they can also swim thousands of meters under the water to explore the mysteries of the deep sea, sinking and floating, and appearing and disappearing freely.
The "behemoth" in the ocean
The Latin name of whale
is derived from the Greek word "sea monster". This shows the awe that the ancients had for these giant creatures that inhabited the ocean. In fact, the body shapes of whales vary greatly. Small ones are about 6 meters long, and the largest ones can reach more than 30 meters. The heaviest ones can reach more than 170 tons. , even the lightest one weighs 2,000 kilograms.
Appearance characteristics
Most of them live in the ocean, and only a few species inhabit freshwater environments. Their body shapes are very similar to fish, and they are all streamlined and suitable for Because they are good at swimming, they are commonly called whales, but this similarity is just a convergence phenomenon in biological evolution. Because cetaceans have the characteristics of viviparity, lactation, constant temperature, and breathing with lungs, which are completely different from fish, they are classified as mammals. The heartbeat of a whale is generally 9 to 10 times per minute.
Other species
Sicklefin dolphin, sicklefin spotted dolphin, short-beaked dolphin. The rostrum is short but clearly demarcated from the forehead. The dorsal fin is tall and eye-catching, curved back in a sickle shape, and has a wide base. The back of the body is black or dark gray, the abdomen is white, the front of the head and upper jaw are black, only the snout of the lower jaw is black, and the rest is white. The side of the body is white or off-white from behind the eyes to the ventral side
A collection of killer whale pictures (20 photos). The side of the body is white along the lower side of the dorsal roadbed to the tail base, from the corner of the mouth to the front base of the fins. And there is a black band between the whole anus and the base of the limbs. The front 1/3 of the dorsal fin is black, and the entire back half is off-white. The flippers also have black leading edges and gray trailing edges. The upper and lower parts of the tail fin are black or black gray. Body color varies greatly. There must be 23 to 36 teeth on each side of the upper and lower sides. The adult body length can reach 2.5 meters, the male is slightly larger than the female, and the weight can reach 180 kilograms. They usually form large groups of dozens to hundreds of animals. They divide into small groups when feeding, and then gather into large groups when resting or moving. Lively, swims fast, and often jumps out of the water. The body length is about 1.8 meters. The food is mainly small swarming fish and squid. Killer whales
They are distributed in the East China Sea and South China Sea of ??my country. The whale is an important member of the sea beasts. It is shaped like a fish and is commonly known as a whale. There are many types of whales. There are more than 80 species in the world and more than 30 species in my country's waters.
They are generally divided into two categories. One type has baleen and no teeth in its mouth, called baleen whales, with more than 11 species; the other type has teeth but no baleen in its mouth, called toothed whales, with more than 70 species. The body length of whales ranges from 1 meter to more than 30 meters.
***The most common characteristic
The most common characteristic of cetaceans is that their body temperature is constant, about 35.4°C. The skin is bare, with no body hair, only a few bristles on the snout, and no sweat glands or sebaceous glands. Subcutaneous fat is thick and helps maintain body temperature and reduce the body's weight in water. The skull is well developed, but the brain is small, the face is large, and the forehead bone and maxilla are significantly extended, forming a very long snout. The neck is not obvious, the cervical vertebrae are healing, and the head is directly connected to the torso. The forelimbs are fin-shaped, the toes are not separated, and there are no claws. The joints of the elbow and wrist cannot move flexibly, so they are suitable for swimming in the water. The hind limbs have degenerated, but there are still remnants of the pelvis and femur, which are in the form of remaining bone fragments. The tail degenerates into a fin, and the skin at the end expands horizontally from left to right to form a pair of large tail lobes, but they are not supported by bones. The vertebrae gradually taper off the long and narrow tail trunk, and finally disappear before entering the tail fin. The tail fin is different from that of fish. It can move up and down and is the main organ for swimming. Some species also have dorsal fins for balance. Their bones have sponge-like tissue and there is more fat in the body cavity, which can increase the size of the body and reduce the specific gravity of the body to increase buoyancy. Right whales
Their eyes are small, without tear glands and nictitating membranes, and their vision is poor. There is no external ear shell, and the external auditory canal is very thin, but the hearing is very sensitive, and it can feel ultrasonic waves, and rely on echolocation to find food, contact companions, or escape enemies. There are 1-2 external nostrils, located on the top of the head, commonly known as the blowholes. Generally, the farther the nostrils are located, the higher the degree of evolution. Breathe with the lungs. There are two lungs on the left and right. There are many capillaries in them. They are elastic and can help the circulation of oxygen and adapt to the gas exchange on the water surface. You need to surface for ventilation every once in a while. Can dive for longer periods of time. There are 10 to 20 pairs of ribs. The stomach is divided into 4 chambers. The kidneys are mostly tumor-like. The testicles of male animals are located in the abdominal cavity. The female animal gives birth and breastfeeds in the water. The uterus is bicornuate and has a pair of breasts located in the cleavage on both sides of the reproductive slit. There are slender nipples. The milk is rich in calcium, phosphorus and a large amount of fat. The young have teeth during embryonic life, but the teeth of baleen whales are replaced by baleen at birth, while the teeth of toothed whales are retained throughout their lives. Narwhal
Whales are social animals. They usually live in groups in the sea. However, when whales breathe, they need to swim to the surface. At this time, whales use the blowholes on their heads. Come breathe, and when you exhale, the moisture in the air condenses to form the familiar fountain shape. Experts can even identify the species of whale based on the height, width and angle of the water jets. There are many types of whales, roughly divided into two categories: toothed whales and baleen whales. There is a very thick layer of fat under the epidermis of the whale, which is commonly known as whale oil. It can keep the whale body warm and store energy to supply emergency needs. Because the whale has many special structures in its body, it can hold its breath and slow down its heart rate in the water for a long time. Therefore, when it sinks to the bottom of the sea, it will always take a long time before it resurfaces. In addition to having a structure for storing oxygen, when a certain part of the body requires a large amount of blood supply, the body also has a special function to centralize the supply.