New findings from Auburn University in the area of hormones published.

"To better understand the proximate causation of the two major types of mating seasons described for North American pitvipers, we conducted a field study of the cottonmouth (Agkistrodon piscivorus) in Georgia from September 2003 to May 2005 that included an extensive observational regime and collection of tissues for behavioral, anatomical, histological, and hormone analysis," scientists writing in the journal General and Comparative Endocrinology report (see also Hormones).

"Enzyme immunoassays (EIA) of plasma samples and standard histological procedures were conducted on reproductive tissues. Evidence from the annual testosterone (T) and sexual segment of the kidney (SSK) cycle and their relationship to the spermatogenic cycle provide correlative evidence of a unimodal mating pattern in this species of pitviper, as these variables consistently predict the mating season in all snake species previously examined under natural conditions," wrote S.P. Graham and colleagues, Auburn University.

The researchers concluded: "In most reptiles studied to date, high plasma levels of T and corticosterone (CORT) coincide during the mating period, making the Cottonmouth an exception to this trend; we suggest two possible explanations for increased CORT during spring ...