What are invertebrate animals?

Invertebrate animals are animals that have no backbone and are cold blooded, meaning they cannot regulate their own body temperature, according to the National Wildlife Federation.

Invertebrates make up 95 to 99 percent of animal species, states Smithsonian Zoological Park. Because the only thing they all have in common is the lack of a spine, invertebrates exist in a wide variety of species, classified by five major phyla. Examples of invertebrates include sponges, jellyfish, corals, worms, insects and starfish.

Other features of most invertebrate animals are that they are multicelluar, have tissues, reproduce sexually, have a symmetrical body plan and do not produce their own food.