Thesis (M.S.)--University of Florida, 2003. / Title from PDF title page (viewed on July 4, 2005). Includes bibliographical references (p. 27-33).

Thesis (M.S.)--Missouri State University, 2008. / "December 2008." Includes bibliographical references (leaves 33-37). Also available online.

Thesis (M.S.)--Missouri State University, 2008. / "August 2008" Includes bibliographical references (leaves 23-27). Also available online.

I conducted an integrative field study on male cottonmouths (Agkistrodon piscivorus), a common pitviper of the southeastern United States, to investigate the evolution of contrasting mating patterns in North American pitvipers (bimodal and unimodal annual patterns) and resolve conflicting information about the pattern exhibited by the cottonmouth. I determined a unimodal late summer peak of testosterone (T) and a muted unimodal seasonal cycle of the sexual segment of the kidney (a secondary sexual characteristic), both of which were correlated with the single peak of spermatogenesis in late summer. I also conducted a study to determine diel and seasonal variation of corticosterone (CORT), the effect of captive handling on CORT, and the relationship between CORT and T after captive handling, and detected a significant elevation of CORT and a significant decrease of T after capture in male cottonmouths, as well as a significant negative correlation between CORT and T.

Snake vertebrae are common in the fossil record, whereas cranial remains are generally fragile and rare. Consequently, vertebrae are the most commonly studied fossil element of snakes. However, identification of snake vertebrae can be problematic due to extensive variation. This study utilizes 2-D geometric morphometrics and canonical variates analysis to 1) reveal variation between genera and species and 2) classify vertebrae of modern and fossil eastern North American Agkistrodon and Crotalus. The results show that vertebrae of Agkistrodon and Crotalus can reliably be classified to genus and species using these methods. Based on the statistical analyses, four of the fossil viperid vertebrae from Hickory Tree Cave were assigned to Crotalus horridus, one to C. adamanteus, and another to Agkistrodon piscivorus. The potential presence of the latter two species could indicate that the deposit is from a warm period during the Quaternary such as a Pleistocene interglacial or Holocene warm interval.