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1 April 2015 Sexual Maturity in Male American Alligators in Southwest Louisiana
Valentine A. Lance, Ruth M. Elsey, Phillip L. Trosclair III
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Very little is known about the attainment of puberty in reptiles. In the American alligator (Alligator mississippiensis) males are assumed to be sexually mature at about 1.8 m in total length, but it is not clear at what size they produce testosterone, spermatozoa and mate successfully. We re-examined this question by studying plasma testosterone levels in blood samples from a large sample of alligators (∼1,500) collected every month of the year and ranging in size from approximately 61 cm (2 ft) to 360 cm (11.5 ft). Testosterone values ranged from 0.05–115.41 ng/mL. All size classes of alligators exhibited a seasonal cycle in testosterone levels, but the concentrations were size-dependent: the larger the alligator the higher the testosterone. In all size-classes testosterone reached a peak in the breeding season (March–May). Mean testosterone in the largest size-class during breeding was 75 ng/mL whereas in the smallest size-class peak testosterone was less than 3 ng/mL. The smallest size-class (59–89 cm) showed an additional rise in testosterone in late summer. The attainment of sexual maturity in alligators appears to be closely associated with growth and is a gradual process lasting several years. Sexually immature alligators show a seasonal pattern of testosterone secretion similar to that of adults, but the values are significantly lower.

© 2015 Brazilian Society of Herpetology
Valentine A. Lance, Ruth M. Elsey, and Phillip L. Trosclair III "Sexual Maturity in Male American Alligators in Southwest Louisiana," South American Journal of Herpetology 10(1), 58-63, (1 April 2015).
Received: 30 October 2014; Accepted: 1 April 2015; Published: 1 April 2015

American alligator
sexual maturity
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