Whales catch fish with bubbles.
In order to use this technique, whales gather fish or krill crustaceans in a circle formed by their stomata. When whales rise to the surface, their prey is trapped in the bubble net, where giant humpback whales enjoy a big meal. Scientists found that humpback whales blow bubbles to trap fish. The video recorded this surface predation method called "bubble net fishing".
The Latin scientific name of whale is derived from the Greek word "sea monster", which shows the ancient people's awe of this kind of giant living in the ocean. In fact, the size of whales varies greatly. The small ones are about 1.8 meters long, the largest ones can reach more than 3 meters, the heaviest ones can reach more than 17 tons, and the lightest ones also have 2 kilograms, which are divided into baleen whales and toothed whales.
When the ancients named it, even the word whale itself had a fish character. If it was written with the names of mackerel, Spanish mackerel and other fish, it would be even more difficult for people to know the true face of Lushan Mountain. Not only Chinese characters, but also foreign countries have similarities. For example, German calls whales giant fish. In some natural science books from 16th to 17th century, whales were treated as fish and recorded together with fish.
In fact, although whales look like fish, they are not fish, but a kind of mammals, which is similar to the situation that bats are like birds but not birds, but also a kind of real mammals. Whales, unlike fish, are viviparous. Generally, they give birth to one baby every two years. The young are fed and raised by the mother's milk.
Features:
The common feature of cetaceans is that their body temperature is constant, about 35.4℃. The skin is naked, with no body hair, only a few bristles on the tail, and no sweat glands and sebaceous glands. The fat under the skin is very thick, which can keep the body temperature and reduce the specific gravity of the body in water. The skull is developed, but the skull is small, the face is large, and the forehead bone and maxilla are significantly prolonged, forming a long snout.
The neck is not obvious, but 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 joints of elbows and wrists cannot move flexibly, which is suitable for swimming in the water. The hind limbs are degenerated, but there are still remnants of pelvis and femur, showing residual bone fragments. The tail degenerates into fins, and the skin at the end expands horizontally from left to right, forming a pair of large tail leaves.