Animals can be sorted into groups based on what their bodies are like. Mammals have fur and feed milk to their babies. Birds have feathers and most can fly. Fish live in water and have scales and gills. Reptiles have dry, scaly skin. Insects have six legs and a body in three parts.
Sort pictures of animals into groups. Visit a zoo, farm, or pond and name which group each animal belongs to. Play "Which group am I?" guessing games with animal clues.
There are millions of different animals in the world, so scientists sort them into groups to keep things organized. Animals in the same group share important features — things their bodies have in common. Let's learn the five biggest groups.
Mammals are animals that have fur or hair, breathe air, and feed milk to their babies. Dogs, cats, horses, elephants, and humans are all mammals. Even whales and dolphins are mammals — they live in water, but they breathe air and feed milk to their young. If it has hair and the mother makes milk, it is a mammal.
Birds are animals that have feathers. Most birds can fly, but not all — penguins and ostriches are birds that cannot fly. All birds lay eggs and have beaks instead of teeth. Robins, eagles, parrots, and chickens are all birds. Feathers are the one thing that only birds have.
Fish live in water their whole lives and breathe through gills instead of lungs. Most fish have scales covering their bodies and fins for swimming. Goldfish, sharks, salmon, and clownfish are all fish.
Reptiles have dry, scaly skin and most lay eggs on land. Lizards, snakes, turtles, and crocodiles are reptiles. Their scales feel dry and smooth — not slimy like many people think! Insects are small animals with six legs and a body in three parts. Ants, butterflies, beetles, and grasshoppers are insects. Insects are the biggest animal group in the world — there are more kinds of insects than all other animal groups combined.