is a mammal.

Although the whale has the word fish, it is not a fish, but a mammal living in water. It has the same physiological characteristics as terrestrial mammals, such as breathing with the lungs, constant body temperature, viviparous and so on, and has some special physiological structures evolved to adapt to the aquatic environment. Whales are viviparous like mammals on land, and young whales are born directly from the mother's belly.

Precautions:

Whale has a very thick fat layer under its epidermis, which is called whale oil, which can keep the whale warm and store energy for emergencies.

Because whales have many special structures, they can hold their breath in the water for a long time and slow down their heartbeat, so when they sink to the bottom of the sea, it will take a long time to surface again. In addition to the structure of storing oxygen, when a certain part of the body needs a large amount of blood supply, there will be a special function of centralized supply in the body.