Date of Graduation

Spring 2019


Master of Science in Biology



Committee Chair

Day Ligon


Macrochelys temminckii, BCI, dual energy X-ray absorptiometry, stress, corticosterone, stress response

Subject Categories

Aquaculture and Fisheries | Biodiversity | Endocrinology | Integrative Biology | Other Physiology | Population Biology | Zoology


The alligator snapping turtle (Macrochelys temminckii), is a species of conservation concern that is the subject of multiple head-start and reintroduction efforts across its range. In captive propagation programs, producing offspring that are in optimal physiological condition maximizes the likelihood of success after release. The purpose of my study was to compare stress and body composition between one free-ranging reintroduced population and two captive populations. The two captive populations were both housed in southern Oklahoma, but one group was reared indoors whereas the other inhabited outdoor ponds at a national fish hatchery. I used circulating glucocorticoid (corticosterone) concentrations as an indicator of stress level and dual-energy X-ray absorptiometry (DXA) to estimate body composition. Corticosterone concentrations did not differ between captive and free-ranging populations, possibly suggesting that corticosterone is a poor predictor of stress in this species or under chronically stressful conditions. DXA accurately and precisely estimated fat mass (FM), lean tissue mass (LTM), and bone mineral mass (BMM). The captive-outdoor and free-ranging populations exhibited greater BMM than the captive-indoor population. However, both captive populations exhibited higher FM and lower LTM than turtles in the free-ranging population. A body condition index calculated by regressing log-transformed mass on length did not correlate with FM or BMM, but did correlate significantly with LTM.


© Brandon Scott Tappmeyer

Open Access