Invertebrates Animals which don t have a backbone or skeleton, are called Invertebrates. Insects Adult insects typically have three pairs of legs, one pair of antennae and in most instances, two pairs of wings. Vertebrates Animals which have a backbone or a bony skeleton, are called vertebrates. Fishes and all diverse group of animals that live and breathe in water. Most fishes have fins for swimming, scales for protection and a streamlined body for moving easily through the water.
Reptiles are vertebrates that have a backbone with tough, dry skin covered with horny scales.
Some of the most widespread living reptiles are turtles, lizards, snakes, crocodiles and alligators. They can live on land and in water. Mammals have entirely different habits and behaviours. Humans are mammals. They give birth to their young directly, and don't lay eggs.