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We studied the reproductive cycle of wild Macrochelys temminckii (Alligator Snapping Turtle) in southwest Georgia from March 2008 to September 2010. We measured plasma testosterone (T), estradiol (E2), and corticosterone (C). Seasonal changes in T were observed in males, with maximum concentrations occurring in October. Evidence of mating and male combat were seen in April. Females displayed seasonal changes in T and E2 concentrations, with peaks occurring in March and April, respectively, (in association with mating and ovulation) and again in September and October, respectively, (in association with follicular development and vitellogenesis). We observed oviductal eggs (mean clutch size = 28.5) in April. Concentrations of C were not significantly different between months. Reproductive patterns coincided with seasonal variation in temperature and water level. [ABSTRACT FROM AUTHOR]

We studied the determination of sex for intermediate size classes and adult sexual dimorphism in a Georgia population of Macrochelys temminckii (Alligator Snapping Turtle). We sexed turtles when possible based on size and morphometrics. We took blood samples from captured individuals and measured plasma testosterone using enzyme-linked immunoassay. We examined females and individuals for which sex was unknown using ultrasound to determine sex and reproductive status. We used testosterone concentration to confirm individual sex assignments. For all biometric measurements, adult males were larger than females. Testosterone concentrations were higher in adult and subadult males than in females. Head width did not differ between the sexes when adjusted for body size. Plastron-to-vent length (cm) and testosterone concentrations were significantly greater in adult and subadult male turtles compared to females and were valuable in determining sex of smaller adults >25 cm straight-midline carapace length. [ABSTRACT FROM AUTHOR]