What do invertebrates have instead of bones?

Invertebrates do not have a spine (backbone) like vertebrates do. Fish, Birds, Reptiles, Amphibians, Mammals are vertebrates with internal skeletons, spines, heads, and brains with central nervous systems. All insects are invertebrates and they mostly have exoskeletons (external skeletons), and no backbones. Their internal organs make up the entire contents of their interior structures.