The African spurred tortoise is the third largest species of tortoise and is beaten only by the giant tortoises of Aldabra and Galapagos. Of all wildlife with backbones, Turtles and Tortoises are the only ones that also have a shell, made up of 59 to 61 bones covered by plates called scutes, which are made of keratin like our fingernails. They cannot crawl out of it because the shell is permanently attached to the spine and the rib cage.