"Dinosaur of Turtles" Proves to be Weighty Subject of Study

Florida is well known as home to more than a million alligators. One “alligator,” however, is actually a turtle. The alligator snapping turtle – nicknamed the “dinosaur of turtles” – is the largest freshwater turtle in North America. Its distinctive appearance includes a heavily-ridged shell and a large head with a hooked beak. The alligator snapper lives in river systems from the Suwannee River to eastern Texas. Recent research on Suwannee River turtles suggests that they are physically and genetically distinct from other populations – meaning they could be a separate species. Researchers know little about this Suwannee population, so Fish and Wildlife Research Institute biologists are working to learn more about these turtles and provide the first population estimate.

Beginning in July 2011, project scientists picked 12 sites representing all habitat types along the Suwannee from White Springs to the Gulf of Mexico. Repeatedly at each location, researchers bait hoop-net traps with pieces of fish in the afternoon and check traps the following morning – because turtles are most active at night. Biologists measure and weigh captured turtles and mark them by drilling holes along the margin of their shells and implanting microchips in their long tails. Project scientists also X-ray many of the captured turtles for the presence of swallowed “bush hooks” that anglers suspend from branches along the river to catch catfish. As turtles can die from ingesting these hooks, researchers will use the information to assess the potential effect on the population.

So far, almost one-third of turtles captured weighed between 100 and 125 pounds, which represent large adult males. Researchers think large turtles account for a high percentage of those captured because the population has experienced little harvest pressure and adult males move around more than juveniles and females. The alligator snapping turtle is listed as a Species of Special Concern in Florida, but that designation will be removed after a management plan is approved. If researchers determine the Suwannee turtles represent a separate species, the population data from this project will be crucial in determining that species’ conservation status.

Partners in this project include: Suwannee River Water Management District, Florida State Parks, U.S. Fish and Wildlife Service, University of Florida and Sonotronics.