Why do whales live in the sea?

Ancient whales may be amphibious animals, feeding on fish in the sea during the day and returning to land at night. Primitive whales lived on land by hunting other animals and fish. Later, due to the lure of a large number of fish, they gradually went to the sea.

From the anatomical point of view, many characteristics of cetaceans show a high degree of adaptation to marine life. However, anatomical evidence is not enough to answer many questions about the origin of cetaceans.

However, from the biochemical and genetic point of view, cetaceans are closely related to ungulates, and the fossil record (about 50 million years ago) also supports that cetaceans evolved from ungulates.

The ancestors of cetaceans may be terrestrial ungulates from North America, Europe and Asia-the family Oribatidae.

Some members of middle-clawed animals are petite as domestic dogs and some are tall as bears, but the evolution process of many animals is from small to large, so whales may have evolved from small middle-clawed animals.

It is speculated that these middle-clawed animals, with few teeth, lived in shallow waters, and gradually changed into amphibious life forms in the long evolution process, and then became various whales and dolphins.

Extended data:

There are two kinds of whales, one is baleen whale and the other is toothed whale.

Whales belong to Chordata phylum, Vertebrate phylum, Mammalian phylum and Euvertebrate phylum, including about 98 viviparous mammals living in oceans and rivers. There are more than 30 species in China waters.

All kinds of whales live in the sea except a few whales that live in fresh water.

Cetaceans are completely aquatic mammals, which are very similar to fish in appearance. Its body length is generally between 65,438+0-30 meters, with bare skin, less hair on the nose and mouth and thick subcutaneous fat.

These fats help to keep the body temperature. When they live in water, these fats can reduce their weight and help them swim.

Cetaceans are completely aquatic mammals, and some mainly rely on echolocation to find food and avoid enemies. They generally feed on mollusks, fish and zooplankton, and some species can also prey on seals and seals.

You must take a deep breath every once in a while. Generally, it swims from high latitude cold water area to low latitude hot water area to give birth in winter, and swims back to high latitude cold water area from low latitude to prey in summer.

Baidu Encyclopedia-Cetaceans