CZAAWE Resource Article

Tonic immobility in Anolis carolinensis: Effects of time and conditions of captivity
Publication Type 
Journal Article
Year of publication 
Behavioral Biology
Changes in the tonic immobility (TI) response in Anolis carolinensis were investigated as a function of duration and condition of captivity in five experiments. Although anoles ultimately show significant decreases in durations of immobility with repeated elicitations of the response, there was an increase in both the mean and variance of immobility durations of subjects tested on the third day of captivity. It was demonstrated that this third-day captivity effect depended neither on previous testing nor on crowding. If subjects were captured, released, and then recaptured, however, the third-day effect was not seen. The 3-day captivity effect was also eliminated if subjects were housed in terraria provided with foliage. These findings are discussed in terms of the concept that captivity in unnatural environments exerts cumulative stress on organisms over the initial days of confinement that can be ameliorated by the use of more naturalistic conditions of housing.