[header] How to tell a turtle's age [title] Pick one " scute " to count. [step] You want to count rings on the turtle's scutes to help determine age. The scutes are the scales that cover the turtle's shell. 
Keep in mind, this method only gives you a very rough estimate, as rings often develop in periods of feast and famine for turtles. In other words, they may develop when the turtle was very hungry or had a lot of food, rather than just in winter and summer.