The tortoises are larger in size as compared to turtles. The tortoises are semi-terrestrial in nature and they are present in freshwater too. The turtle on the other hand is present in aquatic and marine form only. The turtle has a heart-shaped carapace whereas the tortoise has an oval-shaped carapace. The fore-limbs and hind limbs of the tortoise are not modified into paddles whereas they are modified into paddles in turtles that help them in swimming. The head of the tortoise can be completely withdrawn into the shell but in turtles, it can only be partially withdrawn into the shell.