* Breathing: Dolphins breathe air through lungs, just like you and me. Fish breathe underwater using gills.
* Warm-blooded: Dolphins are warm-blooded, meaning they can regulate their own body temperature. Fish are cold-blooded, their body temperature changes with the surrounding water.
* Giving birth: Dolphins give birth to live young and nurse them with milk. Fish lay eggs.
* Hair: While they have very little, dolphins do have hair at some stage in their lives. Fish have scales or slime.
* Skeleton: Dolphins have a bone structure similar to other mammals. Fish have skeletons made of cartilage or bone.
Even though dolphins live in the water and look like fish, they share much more in common with other mammals like humans, cows, and dogs.