Date of Graduation

Spring 2022


Master of Science in Biology



Committee Chair

Day Ligon


In contrast to many species of aquatic turtle, Alligator Snapping Turtles (Macrochelys temminckii) are putatively nocturnal. Data supporting this assertion are chiefly anecdotal, however, and two recent studies cast doubt on this generalization. Differences in activity patterns may be related to variability in temperature and photoperiod across the species’ range and may be influenced by ontogenetic changes, as well. To assess this, I equipped juvenile Alligator Snapping Turtles spanning a range of different ages with activity data loggers. I used 4-year-old turtles were to measure latitudinal differences in activity which were reared in hatchery ponds spanning the species’ latitudinal range and located in Kansas, Oklahoma, and Louisiana. I also used 2- and 7-year-olds reared in Oklahoma to investigate ontogenetic changes in activity patterns. Temperature varied predictably with latitude, with warmer water temperatures occurring at lower latitudes. Daily activity patterns defied simple classification, but crepuscular activity was observed more frequently than was predominantly nocturnal or diurnal activity. The effect of latitude on diel patterns was inconsistent, with turtles in Louisiana consistently showing higher levels of activity and occasionally showing differences in daily activity patterns, with peaks of activity occurring where other sites showed lack of activity, from turtles at other sites. Seasonal activity did vary among the three age classes that I tested, with 7-year-old turtles showing higher levels of activity than the other two age classes throughout summer and autumn, and 2-year-old turtles showing higher than expected levels of activity in the winter months. Diel activity did differ some among age classes, but still showed similar periods of high activity around dawn and dusk. My results suggest that the activity patterns of Alligator Snapping Turtles change with latitude and developmental stage and, in combination with previous studies, demonstrate that while nocturnal activity occurs in this species, nocturnality is a poor general descriptor.


Macrochelys temminckii, activity, ontogeny, latitude, temperature, age

Subject Categories

Biology | Terrestrial and Aquatic Ecology


© Parker R. Golliglee

Open Access