Spotting Spotted Turtles

As you may know, the southeastern United States is recognized for its extraordinarily high species diversity of turtles—a number of muds and stinkpots, snappers, softshells, cooters and sliders, to name a few, inhabit this region. Complementing our efforts specific to protect the Gopher Tortoise, Orianne Society staff are now directing some serious energy toward the conservation of a small, mostly-aquatic species, the Spotted Turtle (Clemmys guttata).

Hands-down one of the most beautiful and engagingly-patterned species on the Planet, the aptly named Spotted Turtle is a small, bluish-black turtle with small, yellowish spots on the upper shell and orange and yellow spots on the head. The smooth shells of adult Spotted Turtles are but 3.5–4.5 inches long, thus fitting comfortably into the palm of one’s hand; I have come to think of these docile little turtles as the reptilian version of a soothing stone. The similar in appearance, and more terrestrial, Box Turtle may have handsome yellow colors, but lacks discrete spots and is considerably larger, with a high, dome-shaped carapace.

Historically, their pleasing characteristics resulted in the over-collection of Spotted Turtles for the pet trade in some regions, and in 2012 the species was petitioned by the Center for Biological Diversity for Federal Listing status as “Threatened”. Many populations have become isolated, declined, or disappeared due to habitat loss and adverse impacts to wetlands, and the species is now protected from collection (or collection is regulated) in the states in which it occurs.

Enter The Orianne Society. In 2013, we initiated studies of the Spotted Turtle’s distribution, ecology and conservation status in Georgia—near the southernmost extent of the species’ range. I compiled each and every Spotted Turtle record (i.e., museum specimen or observation supported by a photograph) for Georgia that I could locate—from a review of museum specimens and the literature, and from a questionnaire broadcast to biologists and naturalists soliciting their observations. In doing so, I found a grand total of only 130 records for the state, the first records going back to April, 1892, when two adult specimens were collected over successive days in mid-April at a large rice plantation in coastal Georgia; these specimens are still housed at the United States National Museum in Washington, D.C.

Some notable information emerged from my effort. Over 90% of the 130 records were of turtles observed or collected from mid-February through mid-May; it was good to document this, although it isn’t terribly surprising, as these months correspond to the peak period of Spotted Turtle activity in nearby states to the north (NC, SC, VA) and south (FL). Over half of the records were turtles found crossing roads and half of this complement was found DOR (dead-on-road). Observations of male turtles greatly outnumbered observations of females, and, interestingly, all but three records are based on adult-sized turtles. As far as we know, a hatchling Spotted Turtle has never been found in Georgia.

Hatchling Spotted Turtles emerge with but a single spot per scute; spots increase in number with advancing age. In actuality, the spots are transparent “windows” in the scutes overlaying deposits of yellow pigment. Some adults will eventually develop over 100 spots. These spots are simply thought to enhance the turtle’s camouflage—I can vouch that they are hard to see as they puddle about in the leaf litter of duckweed-splotched, tannin-stained waters, under dappled light.

This year we initiated Spotted Turtle mark-recapture studies at several sites in Georgia, including The Orianne Indigo Snake Preserve. We also have intensive field studies investigating home range size and habitat use planned for the near future in this region. Orianne Society volunteer Matt Moore and I spear-headed the mark-recapture efforts, finding good numbers of turtles by employing both wading surveys and by trapping (using small traps designed expressly for capturing Spotted Turtles).

I am excited to report that we captured and marked over 30 spotted turtles this Spring. Notably, five of these were very small juvenile or subadult specimens. Turtles are marked by the time-tested method of notching marginal scutes, with one to three scutes notched per turtle (and we also photograph the unique patterns on both the upper and lower shells of our charges).

As mentioned above, late winter through May is “Spotted Turtle Season”—they wake up, warm up, bask, bask some more, feed ravenously, find each other, bask some more, and mate, mate, mate. An idyllic April afternoon found me sitting on the damp bank at the edge of a blackwater pool, marking a gorgeous adult female Spotted Turtle, feeling good about doing some good for Clemmys guttata. You can spend many minutes hypnotized, lost and far from thought, considering the beauty of these little reptiles. The black and melon colors on opposites sides of her plastron were symmetrical and you could connect the spots on one of her carapace scutes to form The Big Dipper. Entranced, I almost missed noticing the big male Clemmys that popped up in the water just offshore. He looked intelligent as he cast me a glance, blinked twice, and slowly turned his head to survey the pool.

We anticipate recaptures of many of our marked turtles in future field seasons. Based on a long-term, mark-recapture study conducted in Ontario by Jacqueline Litzgus, Spotted Turtle survivorship and longevity estimates are among the highest values reported for any animal species, with male and female turtles potentially living up 65 and 110 years, respectively. Our work in the field will help decipher many aspects of this species’ life history and ecology in a region where it has been little studied, and we are eager to learn more.