Eastern box turtles are a familiar resident in much of the eastern United States. Many of us, including myself, link these iconic reptiles to our childhood memories. Growing up in the suburbs of Cincinnati, I recall one particular box turtle (who had a missing limb, making the animal easily recognizable and something of a neighborhood celebrity) that made an appearance year after year, despite the missing appendage. We assumed our shelled friend was male and referred to “him” as such, but I had no real way of knowing if that was the case.
So, how can one decipher between Mr. Box Turtle or Ms. Box Turtle? The next time you encounter a box turtle, observing the characteristics listed below can help you reveal the gender of the turtle. Keep in mind, one or two characteristics is not enough to go on. Shelly, the Arboretum’s resident box turtle, was once named Sheldon on account of her deceptive eye color and shell. Once she laid an egg, however, a name change was clearly in order.
- Eye color.
Many people may base their assessment of gender on this factor alone, which is perhaps the most widely-known method. Generally speaking, male box turtles have red eyes while females’ eyes are brown. - Shell and head coloration. Male box turtles, as with many other organisms of the male persuasion, are often more brightly and distinctively colored than their female counterparts. Once again, keep in mind that a single characteristic such as coloration is not sufficient enough to offer a definitive answer.
- Rear edge of carapace. The carapace, or top shell part, can also reveal clues towards the gender. A male box turtle’s carapace flares outward, while a female’s does not. This is a very reliable characteristic, once you know what to look for.
Concave or flat plastron. The underside of the shell, or plastron, is also a handy indicator to help reveal the gender. Males have a concave dip within their plastron (which helps the fella out during reproduction) while females generally have a flat plastron. Females, at times, can have a shallow concavity, so don’t rely on this characteristic alone.- Rear claws. Females have longer and thicker rear claws to aid when digging a nest, which usually occurs in the evening hours. However, mother box turtles may have delayed implantation as they have been known to lay fertile eggs up to four years after mating!
So why bother knowing a box turtle in such a personal fashion? In the case of Arboretum staff, as well as other members of the Box Turtle Connection, this and other information (such as age, weight and length) are crucial in understanding the overall health of the box turtle population. Since the Arboretum began monitoring box turtles in 2013, we have marked and released 39 adult individuals, 19 of those being female and the remainder being male (with another 13 juveniles that do not display the above characteristics). This fairly even ratio of males to females, as well as the presence of young turtles, is an indicator that the population of box turtles within the Arboretum is doing well. However, the status of the Eastern box turtle, the official state reptile of North Carolina, is not faring so well overall. Habitat destruction, mortality from automobiles and diseases such as ranavirus are all taking a toll and leading to a decline in their numbers. While they are not currently state-listed as threatened or endangered, the International Union for Conservation of Nature and Natural Resources (IUCN) recognizes them as “vulnerable.”
Bring back the turtles!
How can you help in restoring these wonderful creatures? Monitoring and tracking an Eastern box turtle’s presence helps aid researchers and scientists in determining the status of this species in particular areas. 
Wildlife biologists rely on data from The North Carolina Arboretum and other members of the Box Turtle Connection to aid in their understanding of how these organisms are faring in our state. You can also serve in this regard by participating as a Citizen Scientist (everyday people who report observations of wildlife). This can include submitting your observations to online citizen science resources such as the Carolina Herp Atlas and iNaturalist.org.
On Saturday, May 21, from 10 a.m. to 2 p.m., the Arboretum will hold its third annual Box Turtle Day. Arboretum staff and guest presenters will demonstrate how box turtles are monitored using radio telemetry and other methods, and also discuss ways everyone can help box turtles. The event will include family-friendly activities including crafts, stories and a hike along the Arboretum’s TRACK Trail, developed in partnership with the Blue Ridge Parkway Foundation’s Kids in Parks.
Whether it’s Mr. or Ms., box turtles are an important element to our ecosystem and your efforts can help play a major part in ensuring their survival.