Mammals are animals that nurse their young and have hair. Young mammals develop within the bodies of their mothers and after they are born cannot take care of themselves right away. Many mammals care for their young for many years before they are ready to take care of themselves. Mammal mothers nurse their young.

Mammals have hair or fur, though sometimes not a lot. Most mammals have four “appendages.” These can be legs, hands, flippers, or wings. Mammals are vertebrates, which means that they have a backbone, and warm-blooded, which means that they create their own heat within their bodies. Cows, lions, squirrels, whales and giraffes are all examples of mammals.