INVERTEBRATESMammals, amphibians, reptiles, fish and birds all
have backbones. All these animals make up less than 4% of the total
Over 96% of all the animal species on earth are invertebrates.
are cold blooded animals that do not have backbones and do not have a
skeleton of bone, either internal or external. Some have fluid-filled
skeletons, while others have hard exoskeletons, or outer shells.