Measure box turtle shells

Targeted age group: Grades 6-8
Eastern box turtles are long-lived reptiles living in woodland areas throughout the eastern United States. In this activity, students will learn how to age box turtles and distinguish between male and female turtles. They can also practice taking size measurements on box turtles in photos scaled to the true-life size of wild box turtles on Long Island.
To age box turtles, students need to count the rings on each scute on the turtle’s carapace. The carapace is the hard, upper shell of the turtle and the scutes are the bony plates making up the carapace. For box turtles aged 1-14 years, there will be one ring for each year of the turtle’s life. For box turtles 15 years and older, the rings get close together or may be worn away.  For these reasons, biologists often just categorize older box turtles as “15+ years”. Older box turtles also often develop deep groves between their scutes.
To sex box turtles, students need to observe the shape of the plastron and the carapace. The plastron is the part of the turtle’s shell forming the underside or belly. Male box turtles have a flared carapace, a depression in the plastron, and their carapace is “pinched” at the hind end. Female box turtles do not have a flared carapace and they have a more domed carapace. Keep in mind, though, that these sex differences are not apparent in box turtles aged 7 or younger!
For visuals to help you in aging and sexing box turtles, be sure to check out the guide sheet below.
Materials needed:
Guide to aging and sexing box turtles
Box turtle shell photos for measurements – white background
Box turtle shell photos for measurements – black background
Box turtle shell datasheet
Lisa Prowant, Dawn Nachtigall, Catherine Markham
Box turtle

A young box turtle studied by biologist Lisa Prowant