Aggressive Basking Behavior in Eastern Painted Turtles (Chrysemys picta picta)

Aggressive basking behavior was a frequent and conspicuous part of the daily activities of free-living Chrysemys picta picta in northern Virginia. Inter- and intra-specific interactions included open mouth gestures, biting, and two previously undescribed behaviors: lateral and vertical displacement. Aggression was most frequent from 0900-1000 h, at water temperatures between 30-32 C. Basking turtles avoided potentially aggressive encounters by averting faces while basking and moving away from approaching turtles. Directionality of behavioral interactions was strongly influenced by relative body size. Aggressive behavior was positively correlated with the number of turtles basking, the frequency of emergences, and water temperature.