Instructions
Evaluate the color of the shell. Often older turtles will have shells that appear darker than the younger ones.
Examine the turtle shell for damage. A shell with less scrapes and scratches could indicate a younger turtle, while older adults show much more visible wear and tear.
Turn the turtle over and look at the scutes. A scute is a large bony plate on the underside of the turtle's shell. Scutes have distinct patterns and lines which can be counted that give an indication of age. As the shell grows, the number of scutes does not change, but their size does. Box turtles for example, develop growth rings on each scute similar to the annual growth rings on a tree. These growth rings enlarge in diameter as new keratin forms. Keep in mind that young turtles, up to 10 years old, have rings that are easy to count. After the age of 15, these rings become more obscure and difficult to rely upon. Scutes become less distinct with age, taking on a grayish color and flattened look. Old turtles have scutes that appear sunken in, as calcium depletes from the bony shell.
How to Figure Out the Age of a Turtle
A turtle's lifespan can vary greatly depending on the species. The average lifespan for most turtles is estimated to be anywhere from 30 to 100 years, with some turtles to be believed to be even older. As a result, some pet turtles have seen more than two generations of owners as they have outlived their human caretakers. Determining the exact age of any turtle is nearly impossible, but approximating an age range can be done by following a few easy steps.