Lungfish appeared about 400 million years ago and is one of the oldest existing fish. Many creatures of its contemporaries and even those that appeared later than it have become extinct due to various reasons. However, due to its unique and "advanced" respiration, the lungfish has withstood many harsh environments and survived until now, and is known as " "Living Fossil".

Modern lungfish all live near the equator in the Southern Hemisphere. But according to the fossils that have been discovered, lungfish were distributed in almost all waters on the continent more than 200 million years ago. This strange phenomenon has long puzzled scientists. It was not until the rise of the "plate" theory in the field of earth science that people found the answer.

It turns out that about 200 million years ago, all the landmasses on the earth were basically connected together, called "Pangaea" or "United Continent". All the different bodies of water could communicate in different ways, which allowed the lungfish to spread widely across the "United Continents."

Thereafter, the United Continents disintegrated due to the motion mechanism within the Earth. As seafloor spreading continues to intensify, the fragmented continental masses are like icebergs in the ocean, drifting in different directions. After about 100 million years, the earth gradually became what it is now. Of course, the lungfish living on it "went their separate ways". However, due to environmental and other reasons, most species became extinct. Only three types of lungfish survivors near the equator in the southern hemisphere remained and survive to this day.

Therefore, lungfish is also a witness of "continental drift".