Are Whales Fish? Understanding Whale Animal Classification in One Article

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 enormous in size; the smallest known species is still over 6 m in body length. Toothed whales vary greatly in body size, with the smallest species only about 3 decimeters in body length and the largest also over 20 m. Let us take a look below at whether whales are actually fish!

Are whales fish?

Whales are not fish. Whales are the collective term 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 nurse their young in water, and among all species, except for a few that live in freshwater, the others all inhabit the ocean.

What do whales eat?

Whales generally feed on mollusks, fish and planktonic animals, 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 whales, especially some large members, have been widely hunted because of their high economic value, and many cetaceans are already on the brink of extinction.

What were the ancestors of whales?

The ancestors of whales were most likely terrestrial hoofed animals 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 the evolutionary process of many animals is from small to large, so cetaceans may have evolved from small mesonychids. It is speculated that these mesonychids, which had few teeth and caught fish in shallow-water areas, gradually changed to an amphibious lifestyle and then, over a long evolutionary process, became today's various whales and dolphins.