Dominance Hierarchies in Captive Painted Turtles (Chrysemys picta)

We investigated dominance in two groups of captive painted turtles, each over a period of 8 weeks. In each case, we began with five turtles, then added a sixth after 6 weeks. One group was run in the fall, the other in the spring, and the makeup of males and females differed in the two seasons. We measured two behaviors while they were feeding: mounting, defined as placing a claw or head above the carapace of the other turtle for at least one second, where the mounter was stationary, and biting, defined as snapping at another turtle. We hypothesized that the turtles would demonstrate a dominance hierarchy. Our results showed that painted turtles show individual differences in behavior. These differences are consistent over time and allow dominance hierarchies to be established. Both mounting and biting demonstrated consistency, but mounting was more consistent than biting. The amount of mounting and biting differed by sex and season, but turtle size did not seem to influence their activities. Finally, the introduction of a new turtle disrupted the dominance behaviors of the turtles, suggesting that turtles recognize a new turtle as unfamiliar. Understanding the complex dynamics of captive turtle populations has implications for the management and welfare of turtles in captivity and in the wild.