Tortoises and turtles are both reptiles from the order of Testudines, but in different classification families. The major difference between the two is that tortoises dwell on land, while turtles live in the water some or nearly all of the time.
The bodies of tortoises and turtles are both shielded by a shell, the upper part of which is called carapace, with the lower portion called a plastron. The carapace and the plastron are attached by a bridge, which means that though the head and limbs of a turtle or tortoise may be withdrawn from the shell, the whole body can never be totally detached from it. These reptiles are generally reclusive and shy in nature.