Are Whales Fish?


Whales are not fish. But how do you know? You can tell the difference by watching the animal and asking yourself three questions:

Does its body move sideways or up and down when it swims?

Fish, including sharks, propel themselves through the water by using their body muscles to push their tails side-to-side.

Whales and dolphins push their tails up and down. The dolphin’s body muscles can generate enough power to push it through the water at speeds up to 20-30 miles per hour. That’s faster than you ride your bike, even at top speed.

Does it have gills or a nose?

Both fish and whales need oxygen. Fish use gills, open flaps along the sides of their bodies, to take oxygen from the water. A whale uses its nose and lungs, like you do. It’s hard to see a whale’s nose. It doesn’t stick out the way yours does because whales need streamlined bodies to help them swim fast. And they need a nose on the top of their head so they can breathe while the rest of their bodies are in the water.

So when you’re on a whale watch boat, look carefully. If you see something with gills, it’s a fish; If you see either one or two holes on the top of the head, it’s a whale and those are the “blowholes.”

Does it have a baby swimming with it?

Fish lay eggs and then leave the baby fish to grow up on their own. Whales and dolphins give birth to babies, just like people do. And then they feed and care for their babies for several months, sometimes even for several years. So now that you know the questions to ask, you should be able to tell that a whale is not a fish.