Whales and Fish: Alike but Different
Whales and fish share the ocean. Both have smooth bodies that glide along, and both are good swimmers. A whale might even look like a very big fish at first. Even so, whales belong to a different group from fish.
Start with breathing. A fish takes in air from the water through its gills. A whale has lungs, just as you do, so it must rise to the surface for each breath. The air goes in through a blowhole at the top of its head.
Look at the babies. Most fish lay eggs, and the baby fish hatch out. A mother whale gives birth to a live baby, called a calf. The calf feeds on milk that its mother makes.
Look at the tail. A fish moves its tail from side to side. A whale moves its tail up and down.
Finally, a whale is a mammal, like a dog or a cat, and it is warm blooded. Most fish are cold blooded. These differences set whales apart from fish.