Animals can be divided into 2 groups - invertebrates and vertebrates.
Vertebrates are animals with a backbone. Invertebrates are animals that do not have a backbone. Examples of invertebrates are insects, bugs, snails, and slugs.
Vertebrates can further be divided into 5 groups - amphibians, birds, fish, mammals, and reptiles.
Amphibians are animals that start out as water animals, but grow up to be land animals. Amphibians include frogs and salamanders. Mammals are warm-blooded and have babies that drink milk. Mammals include dogs, cats, and horses. Reptiles are cold-blooded. Reptiles include animals like snakes and turtles.