Molluscs, one of the largest groups in the animal kingdom, have soft bodies and generally have a hard shell for protection – so they are often called “shellfish”. Most molluscs are found in the ocean, but many can be found in freshwater and on land. Worldwide there are about 100,000 species of marine molluscs.

Which animal has hard shell on its back?

Armadillo is a Spanish word meaning “little armored one” and refers to the bony plates that cover the back, head, legs, and tail of most of these odd looking creatures. Armadillos are the only living mammals that wear such shells.

Why do animals have hard shells?

To survive the evolutionary arms race, many animals have developed hardened exteriors to protect themselves from predators. Shells are heavy structures, so few vertebrates aside from turtles and a few armored mammals bear them; instead, most shelled creatures are invertebrates.