Animals that have fur or hair are called mammals. Horses, cows, and dogs are all mammals. Humans are mammals too. Mammals use lungs to breathe. Dolphins and whales live in water, but are mammals because they have lungs. They need to come to the top of the water to breathe the air. Most mammals give birth to live young. Before the animals are born, the mother must carry them inside of her. When the animals is born, it cannot take care of itself. The mother animal helps to take care of it and teach it things it needs to survive. The parents often teach their baby or babies how to find food. When a baby animals learns everything it needs, it is able to live on its own. There are many types of mammals. Some mammals don't always fit all of the traits that are listed in the paragraph above. For example, a koala is one of the few mammals that carry their young in a pouch. An anteater has fur and lungs, but is a type of mammal that lays eggs. Bats are the only mammals that can fly.