These creatures are a family of Testudinidae; land-dwelling reptiles in the order Testudines. They are shielded from predators by a shell – the top part of the shell is the carapace, the underside is the plastron, and the two are connected by the bridge. The carapace is fused to both the vertebrae and ribcage, and they are unique among vertebrates in that the pectoral and pelvic girdles are inside the ribcage rather than outside. Tortoises can vary in size from a few centimeters to two meters. They are usually diurnal (activity during the day) animals with tendencies to be crepuscular (active primarily during twilight) depending on the ambient temperatures, and are generally reclusive animals. The American Society of Ichthyologists and Herpetologists uses “turtle” to describe all species of the order Testudines, regardless of whether they are land-dwelling or sea-dwelling, and uses “tortoise” as a more specific term for slow-moving terrestrial species. However, generally “turtle” is restricted to aquatic turtles, and terrapin may refer to turtles that are small and live in fresh or brackish water. Most land-based tortoises are herbivores, feeding on grasses, weeds, leafy greens, flowers, and some fruits. Too much protein is detrimental in herbivorous species, and has been associated with shell deformities and other medical problems. Credit:Wikipedia.