Research Update: Exciting Developments from our Suwannee Alligator Snapping Turtle Projects


Suwannee Alligator Snapping Turtle captured from the northern end of the Okefenokee Swamp – Ben Stegenga

I wrote last year about our work surveying for Suwannee Alligator Snapping Turtles (Machrochelys suwanniensis) in Georgia as part of a range-wide assessment of the species’ distribution and status. Since that time, there have been several exciting developments in our work with alligator snapping turtles. We have continued to opportunistically conduct trapping surveys in locations with few or no records and have been on the lookout for verifiable reports of M. suwanniensis in Georgia. Several publications highlighting our work along with the work of colleagues are also in progress. It is undoubtedly an exciting time to be working with these charismatic turtles.

The results from several years of surveys in both Georgia and Florida and a compilation of historic records will be published in the upcoming issue of Chelonian Conservation and Biology (Enge et al. 2021). In total, this work compiles 167 records of M. suwanniensis from museum collections, the published literature, and credible observations and combines these observations with the results of 1,893 total trap nights conducted by ourselves and colleagues to assess the distribution and status of M. suwanniensis. Overall, M. suwanniensis appears widely distributed in the Suwannee River watershed but generally occurs at a lower abundance in Georgia. This includes a complete lack of captures from the mainstem of the upper Suwannee River, despite significant trapping effort in this stretch of river. However, sections of the Alapaha, Withlacoochee, and Little Rivers all have vouchered specimens as well as many of their tributaries. This work lays the foundation for future research efforts to fill in distributional gaps and to focus on other aspects of M. suwanniensis ecology and population biology.

The distribution of the Suwannee Alligator Snapping Turtle in Georgia – Houston Chandler

One of the more exciting alligator snapping turtle observations in recent years showed up totally unexpectedly earlier this year. We were contacted by staff at the Okefenokee Swamp Park in Ware County, Georgia who indicated that a large alligator snapping turtle had been picked up by an aquatic weed removal vessel. This individual turned out to be a 470 mm long male M. suwanniensis weighing 23.7 kg (photo at the top of the article). This individual represents an approximately 37 km range extension to the northern reaches of the Okefenokee Swamp. The closest records are from the eastern edge of the swamp in the Suwannee Canal, including an individual that was photographed in 2019 (Stevenson et al. 2021). These recent records from the Okefenokee are tantalizing indicators that a population of alligator snapping turtles may occur within the swamp. However, a dedicated survey effort is needed to better understand the distribution and abundance within the Okefenokee, which has never been systematically surveyed.

Suwannee Alligator Snapping Turtle in a dry floodplain swamp – Houston Chandler

The U.S. Fish and Wildlife Service has proposed listing M. suwanniensis as Threatened under the Endangered Species Act. Current threats facing this species include illegal harvest, by-catch from fishing activities, and habitat alteration. Furthermore, many populations have already suffered significant declines from commercial harvest during the 20th century. Like most turtle species, M. suwanniensis is poorly adapted to changes that increase adult mortality rates. Encouragingly, there seems to be significant conservation interest for both species of alligator snapping turtles. In addition to the impending listing decision, there will be an upcoming issue of Southeastern Naturalist focusing entirely on alligator snapping turtle natural history and research. For such a poorly studied species, this type of effort will have large benefits on future conservation efforts.


Literature Cited

Enge, K.M., D.J. Stevenson, T.M. Thomas, G.R. Johnston, J.B. Jensen, B.S. Stegenga, H.C. Chandler, and P.E. Moler. 2021. Distribution and relative abundance of the Suwannee Alligator Snapping Turtle (Macrochelys suwanniensis). Chelonian Conservation and Biology.

Stevenson, D.J., B.S. Stegenga, B. Rice, J. Barrett, J. Bolton, Z. Cava, H.C. Chandler, K.M. Stohlgren, T. Brock, C.D. Camp, J.B. Jensen, M.D. Moore, S. McGuire, C. Howe, F.H. Snow, J. Oguni, C. Coppola, and L.L. Smith. 2021. New county records for amphibians and reptiles in Georgia. Herpetological Review 52:350–359.