An exoskeleton is a creature that has its skeletal frame on the outside of its body in order for more protection. Most people know these creatures to have shells. So, cockroaches and clams are considered to have an exoskeleton due to their shells. Other animals with exoskeletons include sponges, grasshoppers and lobsters. Many of these animals consist of an exoskeleton that can be made of bone or cartilage.
Unlike a human being who has an internal skeleton where the body grows as the skeleton’s bones grow, the exoskeleton rarely grows. It may grow slightly, but not very much. Since the skeleton is on the outside of the body, the inner body of the animal can’t grow. However, shelled animals may grow and their shell may grow in material as well.
