Are Whales Mammals? Understanding the Classification and Habits of Cetaceans

Whales are mammals, and this is clear in biological terms. They live in the ocean, yet like humans they breathe with lungs and reproduce by giving birth to live young; newborn whales rely on their mother's milk to grow, and their body temperature stays relatively constant. These features all fit the basic definition of a mammal, so whales are not fish, they merely resemble fish in appearance and living environment.

In terms of classification, cetaceans are broadly divided into two major groups: baleen whales and toothed whales. Baleen whales have comb-like baleen in their mouths and feed on swarming prey such as krill and small fish, with the blue whale and humpback whale as common examples; toothed whales have teeth and prey on fish and squid, and the sperm whale and killer whale both belong to this group. Among them, the blue whale is also widely considered the largest animal alive today.

The differences between whales and fish can also be seen in their behavior. They need to surface regularly to breathe, and the blowhole on top of their heads exhales a mist-like spout; their tail fin is horizontal and they move forward by swinging it up and down, whereas most fish have a vertical tail fin that swings left and right. In addition, the ancestors of whales originally lived on land and only gradually adapted to life in the ocean through a long process of evolution.

A common question related to whales is why they become stranded. The reasons are usually complex and may be related to factors such as illness and weakness, navigation errors, tidal changes or interference from man-made sounds. If you encounter a stranded whale, you should promptly contact a professional rescue organization to handle it, and do not drag it yourself or push it back into the sea, so as to avoid causing secondary harm.