Why are Whales Considered Mammals?

Since a whale lives in the water and has a fish-shaped body, why isn’t it considered a fish? The fact is that the whale is a water mammal, and is descended from ancestors that lived on land.

During the thousands and thousands of years they have been living in the water, whales have grown to resemble fish in their shape and other outside features, but they are built and they live like land animals.

A whale’s flippers, for instance, have the bones of a five-fingered hand. Some whales even have the bones of hind legs in their flesh! The most important difference between whales and fish, of course, is that the baby whale is fed on its mother’s milk like other little mammals.

It is not hatched from an egg but is born alive. And for some time after it is born it stays close to its mother, who takes very good care of it.

Since all mammals have warm blood, and the whale has no fur coat to keep itself wrm in the icy water, it has blubber instead. This is a layer of tissue under the skin filled with oil which retains heat and is as good as a fur coat!

Whales breathe differently from fish. Instead of gills, they have lungs and they take in air though two nostrils or “blow holes” on the top of their heads. When they go underwater, these nostrils are closed by little valves, so no water can get in.

Every five to ten minutes, a whale rises to the top of the water to breathe. First it blows out the used air from its lungs with a loud noise. This makes the “spout” which we often see in the pictures of whales. Then the it takes in fresh air and dives down into the sea to swim about.  

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