Arthropods are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. They are invertebrates, which means they do not have an internal skeleton and backbone. Instead, they have a hard exoskeleton on the outside, the top layer of which is known as the cuticle. They can also be different colors. Your skin is different on different areas of your body, and an insect’s cuticle is, too, because it serves many purposes. Because the cuticle is so versatile, this main feature has allowed insects to become one of the most successful groups of animals on Earth.