Date of Graduation

Summer 2021


Master of Science in Biology



Committee Chair

Day Ligon


The Alligator Snapping Turtle (Macrochelys temminckii) is one of many turtle species facing conservation challenges. Nearly extirpated in the 1980s, it is currently the subject of a head-start initiative, of which, any lasting behavioral or physiological effects were—until now—unknown! To evaluate the ability of captive-reared individuals to excel in natural habitats, and to foresee any future research or conservation challenges regarding this animal, I explored a suite of variables that influence bite performance and behaviors including captive or free-ranging status, and environmental conditions including body temperature and season. My results indicated that free-ranging M. temminckii outperform those residing in captivity, and that captive individuals housed in outdoor ponds outperform their counterparts housed indoors. Further, I found free-ranging individuals more willing to engage in bite behaviors, a trend that significantly impacted maximum bite force among test groups. I also found that aspects of bite performance including bite velocity, acceleration, and duration all improve with increases in temperature, and that seasonality significantly influences jaw and lunge movements to an extent that was previously unanticipated, resulting in greater performance at identical temperatures, in the summer than in the Winter. Bite force was relatively robust to temperature and season; but it was maximized at higher temperatures and in the winter. These results indicate that time spent outdoors while in captivity should be maximized to support optimal performance upon release, that rigorous standardization of temperature is required in studies of ectotherm performance, and that care must be taken in selecting the time of year in which temperature studies are conducted.


acceleration, behavior, bite force, free-ranging, head-start, kinematics, latency, Oklahoma, scaling, velocity

Subject Categories

Animal Sciences | Animal Studies | Biology | Comparative and Evolutionary Physiology | Ecology and Evolutionary Biology


© Ashley Herrin Gagnon

Open Access