We know that all the source of the earth's life comes from the ocean. From the organic matter in the ocean, single-cell creatures gradually formed, and then various marine creatures evolved.

With the changes in the earth's environment, some marine life learned to survive on the land, gradually evolved the ability to breathe with lungs, and grew both hands and feet, so that there was such a life circle of life today.

But there is a kind of animal that is very incomprehensible. They are huge, and they have the ability to breathe with the lungs very early. But after evolving to land life, they returned to the ocean to survive.

And, now they are still breeding, which is very incredible. They are whales. From the perspective of life evolution, this is obviously a phenomenon of "atavism".

According to scientists, this may be related to the deterioration of the land environment at that time. At that time, enough food could be found in the ocean, so the early whales gradually gave up surviving on land and living in the ocean.

The common feature of whale animals is that the body temperature is constant, about 35.4 ° C. Whale skin is smooth, without body hair, only a little hair at the tail, no sweat glands, and sebaceous glands.

The skin of the whale is thick, which can keep the body temperature and reduce the proportion of the body in the water.

A whale's heartbeat in one minute was only nine times. Because whale is a mammalian living in water, it has the same physiological characteristics as land mammals, and also breathe with their lungs.

It can hold breathing in water for a long time and slow down the heartbeat. That's why whales can lurk in the water for a long time.

Whales do not drink seawater. On the contrary, they extract water from food through metabolic fat. Although their specific range varies from species, whales live in the ocean around the world. Because whale has a lot of fat, they can easily float in the water.

The sperm whale can dive into the water for two miles, and their bodies have unique physiological adaptability so that they can survive under strong cold, and compressive pressure.

Blue Whale is the largest whale in the world and is also considered the largest animal in the world. The adult blue whale can be 108 feet in length and 200 tons in weight.

The whale's skin is big and hard, and it is the overlord of the ocean. Only humans are their only natural enemies. Before the 16th century, the scale of whaling was not large, and there were many whales in the sea.

Because the entire body of the whale can be used by humans, humans began to kill a large number of whales. This greatly reduces the number of whales.

Today, the problem of marine garbage is getting worse, and marine life is facing very serious problems. As the largest mammal, the whale is threatened even more. More than 300 marine creatures die from marine pollution each year.

In recent years, it has been reported that in other waters in the world, a large number of marine life has died due to swallowing plastic waste. Protecting whales has become the most important thing in the global environment.