Age and litter effects on testosterone levels in young water snakes

To test whether a pulse of testosterone reported in young male garter snake s also occurs in related snakes, testosterone levels were measured in 18 ma le water snakes (Nerodin sipedon) belonging to four litters at 5-6, 16-17, 29-30, and 250-267 days of age. Testosterone levels were uniformly low over the first 30 days of life but increased significantly by 250-267 days of a ge; there were also significant differences among litters in levels of this hormone by that time.