Post-hibernation behavior of a population of garter snakes (Thamnophis sirtalis)

Abstract

The post-hibernation breeding activities of a small population of the common garter snake (Thamnophis sirtalis) were followed in the vicinity of their hibernaculum or den in St. Louis Co., Missouri, USA during the springs of 1981-85, inclusive. Individual males could emerge as early as mid-February and remain at the den and its immediate vicinity for three or more weeks. Each day, after elevating their body temperatures, males patrolled the ground surface within 2-3 m of the den entrance. During patrolling activities, males investigated each other at frequent intervals and often returned to re-enter the den briefly. Upon partial re-emergence, one or more males would assume a position such that the head and anterior portion of the body were elevated. This "blocking"activity may be a behavioral mechanism that controls access to the den by competing males and egress by females. Numerous males simultaneously court a single female. The social organization of garter snakes is compared to that typified by lek species and several similarities are noted.