From the perspective of biological evolution, all the animals in the world originated from the sea and then landed on the ground to conquer the land. But there are also "counter-currents" among them. For example, the ichthyosaurs who returned to the sea 300 million years ago, and the whales that returned to the sea 60 million years ago. Who are the ancestors of whales?
Why did it abandon land and return to the embrace of the ocean? This is a self-denial belonging to the ancestors of whales, and a key choice to create the supremacy of the whale sea. As a member of the mammals, the ancestors of whales did come from land. Paleontologists believe that the closest relatives to whales are four-legged walkers, especially hippos.
About 60 million years ago, the deserts of South Asia were inhabited by fox-sized mammals, and at that time it was a warm and rich beach, and these fox-like mammals were the ancestors of whales. At that time, just 5 million years after the dinosaur mass extinction, marine and terrestrial life had already developed and flourished. These small mammals, which live on the beach, have tasted the sweetness of hunting in the sea.
At that time, the dominant animals in the Earth's oceans were gone, there was a gap at the top of the food chain in the coastal seas, and food became extremely abundant. The whales' ancestors made a key choice, which was to return to the ocean. They return to the ocean with the advantage of mammals, starting naturally higher than fish. After thousands of years of evolution, whales have finally grown into the masters of the oceans, which continues to this day!
Because of the innate advantage of evolution, the whale even monopolizes the two biological chains of the sea, one represented by the baleen whale, which feeds on the large number of plankton and small fish and shrimp in the ocean, directly bypasses the rules of eating small fish by large fish, and with the largest body, preys on the smallest prey, and wins an unprecedented comfortable life. The other is the toothed cetaceans represented by killer whales, which rely on the advantages of mammals to gain the upper hand in the fight with big fish, thus taking away the marine supremacy that originally belonged to sharks.
If it weren't for humans, whales would have lived a much more moist life. Today, the number of individual whales in the world adds up to only 1.5 million, a direct consequence of commercial whaling. Humans coveted the grease of whales and killed millions of large whales in more than a century.
Until today in the 21st century, there are still countries with strange habits towards commercial whaling. What do you think