Turtles have flourished for millions of years on land and in water. They are the only reptiles protected by shells, which are made up of two parts - the upper carapace and the lower pastron. Their webbed feet help them swim.

While it's difficult to distinguish the species of the sunning turtles in this picture, you can tell their sex. The turtle on the left is a male, which has a much larger tail than the female on the right.