Investigating the motivations of repetitive barrier interactions in Pogona vitticeps

Abstract

Considerable research has demonstrated that the effective management of repetitive behaviours such as bar-biting and pacing relies upon understanding their motivations; however, this same research has revealed that repetitive behaviours can have a diverse array of motivations. In reptiles, repetitive behaviours commonly manifest as persistent interactions with the barriers of the enclosure (hereafter IWB). It is typically assumed that IWB indicates a motivation to escape the enclosure, but this has not been investigated; consequently, this assumption is the hypothesis of this article. Two predictions followed from this: IWB should be biased towards known and visible escape routes and should be associated with other factors that may increase a lizards’ motivation to escape. We found that within their enclosures, lizards performed IWB for longer on the only known escape route. Furthermore, when this area was made partially opaque, IWB was biased towards the remaining transparent portion. However, the association of IWB with other factors was less clear. IWB was strongly associated with defecation, but the cause-and-effect of this relationship was unclear. In addition, IWB was not associated with feeding, although this may be related to the generally sedentary life histories of P. vitticeps. Finally, female lizards performed more IWB than males during the breeding season, but the opposite was predicted based on the movement patterns of wild P. vitticeps; this may reflect that IWB is related to the motivation to gain certain resources, but not necessarily to be active. In conclusion, there was evidence that IWB was related to a motivation to escape the enclosure, but as with other research, we found that IWB had diverse motivations that are linked to the animal’s life history.