By Cynthia Rhorback
When you happen upon one of earth’s most reclusive and non-aggressive creatures – the box turtle – do you ever wonder if it’s the same one you saw last time? The intricate yellow pattern on its brown shell may look familiar, but it’s difficult to say for sure if you’ve seen this one before.
We have had similar musings at our house where turtles frequently wander through the yard and garden from spring through fall. Our house is located in the woods of southeastern Lewis County, Tennessee. Deciduous hardwood forest covers the slopes and ridges, separated by numerous small streams. Woods such as these, where there are plenty of worms, insects, mushrooms and fallen wild fruits and berries to munch on, are the favorite habitat of the omnivorous Eastern Box Turtle. The leaf litter of the forest floor provides endless hiding places and soft dirt for a winter hibernation burrow.
On an early June morning hike through the woods near Big Swan Creek, I counted the box turtles who also seemed to be out enjoying the summer morning. But they were definitely on the move, and they were using the existing path for their own highway. That day I encountered a total of 18 turtles, both sexes, cruising through the woods. For a reputed slow mover, I continue to be amazed at how fast a turtle can go when it has a purpose. Perhaps they were motivated by scent that morning and were on the lookout for a mate.
Since they carry their shelter on their backs and the two parts of their shell close tightly, box turtles are fairly well-protected from predators. The raccoon can use its agile hands to pry open a turtle shell, so you may come across an empty one while walking in the woods. I have collected turtle shells for years, marveling at their diverse and beautiful decoration – a living illustration of the wonders of genetics. Even the turtles themselves, their legs, head, neck and tails, have a variety of coloration from nearly red to bright orange or yellow highlights on a brown background.
What began as an interest in turtle shells grew to a curiosity about the box turtles that frequent the immediate area of our home. With my background in Field Biology, I have read several mark-and-recapture studies of wild animals. In September 2009, I started an informal study of box turtles with my husband’s assistance. When we find a turtle in our yard, flower gardens or vegetable garden, we mark it on the back of the shell with a consecutive number, painted with red, nail polish. Turtles that are recaptured get their number renewed because the nail polish can rub off with time. We also started a Turtle Data Log in which we note the date, where the turtle was found, if it is male or female and the length of its plastron (the shell on the underside of the turtle). The mature turtles we’ve encountered have plastrons at least 5” long.
To tell the sex of a box turtle, look at the plastron. Female turtles have a fairly flat plastron, while males have a concave depression that is useful for mounting females. Males often have dark orange or red eyes, while females’ eyes are usually light orange or brown. In combination with the plastron-character, eye color can verify sex. The shape of the shell on mature turtles is also indicative of sex, with the male’s shell being flatter on top while the female’s is highly domed.
Although box turtles seem ubiquitous, using habitats from grassy fields to forests, they are threatened by man’s development of the landscape. Their habitat is continually fragmented and cut up by roads – a veritable threat to the turtle’s existence, especially after a spring or summer rain when they are commonly seen crossing the road. If you’re like me, you stop and get out of your car on country roads to safely move a turtle to the other side.
Lawn mowers and tractors are a serious hazard for box turtles. If turtles live in your vicinity, take a quick walk-through of the area before mowing to check for turtles. In our Turtle Log, we note if the shell is damaged. Many times scar tissue will form, and the shell will mend somewhat. Other times, chunks are missing from the shell edges, which do not regenerate.
You might be surprised that over the two summers we’ve been marking turtles, we have a total of 17 in our Turtle Log. The summer of 2011 was especially active for us. Four of the 17 have been encountered several times, so we consider them “our” turtles — #3, #7, #11 and #14. In other words, their home range appears to be about the size of our large yard – maybe 300 feet in any direction from the house. Two of our closest neighbors have both found turtle #7, a female, in their yard and garden. Turtle #3 is a female, seen most often hanging around the yard, sometimes as close as our front and back porches. Turtle #11 is male and is also very bold. Two days ago he was trying to mount turtle #3 right outside our basement door. Turtle #14, a female, has been found in our and our neighbor’s gardens, but not near the house. Only four of the 17 turtles were male. We have no explanation for this unbalanced ratio.
Many of the others, the mature ones at least, may have been on the edge of their home range when they wandered into our yard. We hope to find them again, alive and well, at some future time. Several of the other turtles were immature and may not have lived long enough to make it into our yard again. Turtles can live as long as 30-40 years, but these are the lucky ones. Although a female may lay hundreds of eggs over her lifetime, there is a high level of mortality. Turtles do not reach sexual maturity until age 7 to 10 years, a relatively long time, biologically speaking. Since they do not mate for life, nor do they raise their young, turtles are on their own after hatching.
Our turtle study has provided some interesting entertainment as well as a heightened appreciation for these solitary creatures. Even though we have several turtles that live in close proximity to us, we would not consider making them our pets. Turtles are wild animals and will have the best life, although full of hazards, in the habitat of their choice where they can come and go at will. A turtle taken as a pet and later released, will try to find its original home range. Foregoing food, water or other needs, it will become exhausted looking for its home and eventually die. People are mistaken in thinking that a turtle carries its “home” on its back and will be able to adapt to a new location.
Our vegetable gardens provide a veritable buffet that may attract box turtles. They love tomatoes, cucumbers, squash and melons. If they begin to be a nuisance, add a one-foot layer of chicken wire to the bottom of your garden fence – it’s pretty easy to exclude turtles since they do not climb. Rather than relocating them far from their home range, a little effort to exclude them is preferable. A turtle can remain its whole, long life in one small area. Imagine its dismay upon being taken in a car and dropped off in an entirely new location. The same is true for snakes, which have a larger home range than turtles. But like a turtle, they will search for home when driven miles away.
Next year we will expand our study to include photos of the turtles. I wish we had been taking photos from the beginning. Photos will add another method of identification and will establish an interesting record of shell variations.
A box turtle study is a project to consider with children rather than adopting one as a pet. There is a lot to learn from observing these humble creatures in their natural environment, doing some internet research, and studying Native American stories about turtles. Find out which other species of turtles live in your area, terrestrial and aquatic. Use the turtle as a starting point for cultivating an interest and respect for nature. There’s a big world out there, ready to provide endless exploration and learning!
Cynthia Rohrbach is a biologist with a 20-year career as a science teacher followed by a 12-year position as an environmental specialist with Tennessee Department of Environment and Conservation. She developed the Green Schools Program to promote and recognize environmental education and stewardship in public and private schools across the state. She is also a founding board member and former President of Swan Conservation Trust, a land trust based in Lewis County which protects hardwood forests and streams for the future. Cynthia and her husband, Steve, have lived in The Farm Community in Summertown for the past 36 years, where they raised four sons.