Whales are mammals that live in the sea. Some whales are very big, and the maximum length can reach 30 meters. Whales are shaped like fish and are spindle-shaped. The head is big, the eyes are small, and the ear shell is completely degraded. The neck is not obvious. The forelimbs are fin-shaped and the hind limbs are completely degenerated; Most species have fins on their backs; The tail is a horizontal fin, which is the main motor organ. Toothed or toothless. One or two nostrils, open at the top of the head. Adults are hairless (many species just have some hair on their mouths). There is a thick layer of fat under the skin, which can keep warm and reduce the proportion of the body. Breathe with your lungs, then inhale on the surface and dive into the water. You can dive 10 ~ 45 minutes. They usually feed on zooplankton, mollusks and fish. Viviparous, usually a calf, is fed with milk. But many people classify them as fish. In fact, they are not fish, but mammals. Distributed in the oceans of the world.

Whales are distributed in all the oceans in the world. It is an aquatic mammal that breathes with its lungs. Its species are divided into two categories: baleen whales, toothless whales, baleen whales and two-nostril whales, such as baleen whales, blue whales, humpback whales and gray whales. Toothed whales have teeth, no baleen whales, only one nostril, such as sperm whales, narwhals, killer whales and so on. Most of the oxygen in the ocean and 60% of the oxygen in the atmosphere are made by phytoplankton. Baleen whales can destroy zooplankton, the number one enemy of phytoplankton. In addition, toothed whales also help to maintain the ecological balance of fish. The toothed whale's food is a large mollusk that feeds on fish. Therefore, without whales in the world, human beings will perish.

We divide whales into two groups:

Toothed whale: Toothed marine behemoths, such as sperm whales, killer whales, dolphins and porpoises.

Baleen whale; Fin whale In fact, these beards are horned teeth that grow in the mouth. They are used to filter water and catch shrimps and other small animals that whales eat. These teeth replace teeth.