Jordan Donini, Florida SouthWestern State College
As most supporters of the Gopher Tortoise council are aware, there are literally hundreds of species that call the deep and winding burrow of the gopher tortoise home, with many of these being fellow members of the class reptilia. Several studies have highlighted the use of burrows by large snake species such as eastern diamondback rattlesnakes (Crotalus adamanteus) and eastern indigo snakes (Drymarchon couperi), along with some smaller species. However, there has been limited documentation or study on how tortoises interact with fellow Testudines (Turtles).
Here in Southwest Florida in a region that will remain secret due to concerns of poaching, my research group and I have been conducting population and home range studies of Florida box turtles (Terrapene bauri) in classic scrub and pine flatwoods habitat. This habitat should immediately trigger visions of gopher tortoise burrows to anyone who has worked with the magnificent species…and this proved to be true at our site! At our particular site in fact, gopher tortoises outnumbered our focal box turtles! Gopher tortoises occur at such densities here that it was likely that some interactions would occur between the two terrestrial turtle species. Thus, a portion of our study was dedicated to documenting any interactions between the densely populated tortoises and the sparse Florida box turtles.
Some previous reports and studies have documented box turtles using gopher tortoise burrows throughout their range, however very few have sought to quantify this use. Thanks to radio-telemetry technology, we were able to regularly track box turtles in gopher tortoise habitat to specifically document how much time they were spending in burrows or with tortoises themselves.
This study lasted for approximately one year and while the major findings will be published in a formal journal, here are the basics we observed.
First, Florida box turtles certainly like active gopher tortoise burrows, though not as much as they like inactive burrows!
We documented 3 of our 10 tagged individuals (2 females and 1 male) all using gopher tortoise burrows multiple times throughout the study. Some turtles spent entire days in active burrows, while others only spent a short time (based on our tracking schedule). However, one male individual (#8) spent almost an entire week in a burrow before moving, and then several months later moved back to that burrow again, spending at least a few days there before moving on. The big difference? This burrow was an old inactive burrow…maybe the lower “traffic” flow was more attractive to the box turtle? Something we’ll have to keep studying to find out!
Through our observations of burrow usage, we anticipated some other interactions between the two species as well. Unfortunately, we didn’t directly observe any specific behaviors. However, the property manager of this specific site did mention to us observations of box turtles and tortoises bumping noses together, in a similar fashion as what may be seen between gopher tortoises during some communication events. This brought with it its own conundrum: We know both of these species can carry Mycoplasma bacteria, so could they be passing it to one another?
Several tortoises had been documented with upper respiratory infection (URI) symptoms likely linked to Mycoplasmosis at this site in the past, but we weren’t sure about the box turtles. During our study, we observed similar symptoms in two of our radio-tagged individuals, seeing watery and swollen eyes, snotty discharge, and lethargy. An additional non-tagged male was also observed with similar symptoms while courting one of the radio-tagged females, bringing the risk of infection with him. While initially worrisome, all of these animals recovered in short time periods without veterinary intervention. In the future investigating the transfer of pathogens between these species in the wild would appear to be a worthwhile endeavor.
Overall, while interactions between gopher tortoises and Florida box turtles were few and fleeting, they still represent an understudied portion of the life history of both species and help pave the way for future study-driving questions as we continue to investigate both gopher tortoises and their wonderful Chelonian cousin commensals.