What is the ancestor of whales, and are whales fish?

Are whales fish? Whales generally refer to animals of the order Cetacea, which mainly include two types: baleen whales and toothed whales. There are fewer species of baleen whales, but they are huge in size, and the smallest known species is still more than 6 m in body length. Toothed whales vary considerably in body shape; the smallest species is only about 3 dm in body length, while the largest is also over 20 m.

Are whales fish?

Whales do not belong to fish. Whales are the collective name for about eighty species of placental mammals in the phylum Chordata, subphylum Vertebrata, class Mammalia, subclass Eutheria that live in the ocean and rivers. They are fully aquatic mammals, and many of their traits show a high degree of adaptation to life in the sea. They suckle their young in water, and among all species, except for a few that live in freshwater, the rest live in the ocean.

What do whales eat?

Whales generally feed on mollusks, fish and plankton, and some species can also prey on seals, fur seals, and so on. At intervals, they must surface to breathe. Generally, in winter they swim from high-latitude cold-water areas to low-latitude warm-water areas to give birth, and in summer they swim back from low latitudes to high-latitude cold-water areas to feed. Due to environmental degradation and extensive hunting by humans, members of the whale group, especially some large members, have been widely hunted because of their high economic value, and many cetaceans are already on the verge of extinction.

What is the ancestor of whales?

The ancestor of whales was most likely a terrestrial ungulate from North America, Europe and Asia——the Mesonychidae. Some members of the Mesonychidae were as small as domestic dogs, while others were as large as bears, but many animals evolved from small to large. Therefore, cetaceans may have evolved from small mesonychids. It is speculated that these mesonychids, which had few teeth and caught fish in shallow water, gradually shifted to an amphibious lifestyle and then, over a long evolutionary process, became today's various whales and dolphins.