The Latin scientific name of whale is derived from the Greek word "sea monster", which shows the awe that ancient people had for such behemoths that inhabited the ocean. In fact, the body shapes of whales vary greatly. The small ones are about 1.8 meters long, the largest can reach more than 30 meters, the heaviest can weigh more than 170 tons, and the lightest can weigh 2,000 kilograms. They are divided into baleen whales and toothed whales. .
When the ancients named it, even the word "whale" itself had a radical of the word "fish". If it is written together with the names of fish such as "tái" fish and "bà" fish, it will make people even more " It’s hard to see the true face of Mount Lu.” This is not only true for Chinese characters, but also similar in foreign countries. For example, German calls whales "Walfisch" (Walfisch). Until the 16th and 17th centuries, some natural science books treated whales as fish and recorded them together with fish.
In fact, although whales look like fish, they are not fish, but a type of mammal. This is similar to the situation where bats look like birds but are not birds, and are also a type of real mammals. Whales are different from fish in that they are viviparous, usually giving birth to one calf every two years. The young are fed by the mother's milk and grow up; fish are oviparous and can lay thousands of eggs at a time. Once the young fish hatch, they can live independently without breastfeeding.
The body temperature of whales is constant, with an average of 35.5°C. It maintains this body temperature whether in cold waters or tropical sea areas; fish are cold-blooded animals, and their body temperatures change with changes in environmental temperature. Whales breathe with their lungs and need to surface frequently to breathe. Fish use their gills to absorb oxygen dissolved in the water, allowing them to stay underwater. The similarity in appearance between whales and fish is caused by them living in the same living environment for a long time, which is a "convergence phenomenon."