Telling Turtles Apart

Male or female? Boy or girl?

Depending on the situation, some variation of the question is pretty common. If you are talking with excited parents who are telling everyone they are expecting, it’s common to ask, “Do you know if you are having a boy or a girl?” If you meet someone in your neighborhood with a new dog, unless the dog’s name is Spike, it’s not unusual to ask, “Is your dog a boy or a girl?”

The HERP ProjectSo it is with the Eastern Box Turtle, one of only two species of box turtles found in the United States and the most common terrestrial turtle in the eastern United States. It is the only “land turtle” found in North Carolina and it is also the state reptile. The students in my story, The 100 Year Turtle Project, were helping researchers find turtles in Orange County as part of a long-term research project to study box turtles. Now they need to learn more about the turtle they found.
So what if you happen to find an Eastern Box Turtle, or Terrapene Carolina? How would you know if it’s a boy a girl?

Here’s a hint... It’s not easy, because box turtles have their sex organs inside their shells. Therefore, secondary sex characteristics must be used to determine the sex of the turtle. Here are a few of these characteristics:

  1. Eastern Box TurtleBody coloration: Male Eastern Box Turtles usually have more colorful heads and legs. They have more red, orange, white and black on their face and neck.

  2. Eyes: The eyes of mature males are usually red or reddish, while the female’s eyes are usually deep brown.

  3. Claws: The back claws of a male Eastern Box Turtle are thicker and curved like talons. A female's back claws are thinner and straighter.

  4. Tails: The tails of male Eastern Box Turtles are thick at the base where it joins the body and it is also longer. The female turtle’s tail is shorter.Plastron of a Male Eastern Box Turtle

  5. Plastron: This is the bottom, or underside, of the turtle. The plastron of many male turtles has a slight concave area, or depression, in the middle. That’s usually the case, but not always. The female plastron is flat.

  6. Shell Shape: Male turtles generally have a more flattened shell. The female turtle’s shell is more round.

Scientists want to know more about the box turtle because our state reptile is among some of the longest-lived and slowest reproducing species in the world.

Eastern Box TurtleThey generally grow very slowly, reaching sexual maturity between seven and ten years old. A mature female box turtle will lay between three and six eggs in a shallow nest in the spring. The eggs are left unguarded and hatch in the late summer or early fall. It takes a long time for an adult turtle to replace itself with a younger turtle. So long, in fact, that if the population is at risk we may not know in time. Box turtles can live to be 50 years or older.

If you happen to find a box turtle, you can become part of the research program and add the information about the turtle you find to the scientific record. Visit the Carolina Herp Atlas to find out how to add the information.

- Frank Graff

Frank Graff is a producer/reporter with UNC-TV, focusing on North Carolina Science Now, a weekly science series that airs Wednesdays, beginning in August 2013, as part of North Carolina Now on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog!

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