Stress in captive Anolis carolinensis lizards

A Green Anole (anolis carolinensis) with extended dewlap in Flamingo, Everglades

A Green Anole (anolis carolinensis) with extended dewlap in Flamingo, Everglades, Florida. (Source: wikimedia)

The main aim of this research was to look into scientific methods for developing welfare guidelines for captive reptiles. The Green anole lizard (Anolis carolinensis) was used to study the effect of long term captivity and specific stressors (environmental provisioning, handling and cage size) on both males and females. The effect of dominance in a multiple male group was investigated and subsequently the presence of personalities in males as well as its effect on predicting dominance was studied.

The findings showed no negative effects of 4 months of captivity in male A. carolinensis lizards. Similar results for females were found for all measurements except body mass and tail width. Here my results indicated a negative effect of four months of captivity on body mass and tail width in females.

Increased or decreased structural complexity of the cage, repeated handling and differences in cage dimensions (range 0.05m³ to 0.2m³) had no effect on body mass, tail base width, heterophil to lymphocyte ratios (H/L ratios), brightness, body colour, behaviour and faecal corticosterone metabolite (FCM) levels. Animals did score very high for several stress-indicating variables in this three weeks preceding these experiments - suggesting that they had experienced considerable stress during capture, transport and temporary housing in the pet store.

The investigation into dominance and personalities showed that dominant males in a multiple male group had priority access to prey and potential sexual partners but may run a higher risk of predation. It could not be confirmed that dominant males in a multiple male group had a higher risk of injuries from aggressive interactions or a higher energetic cost by being dominant. Furthermore, evidence was found for the presence of a behavioural syndrome showing a strong negative correlation between sociability and exploration. Individuals that were less social were more explorative. Finally, it was found that both conspecific tolerance and sociability significantly predicted social dominance and thus that lizards that were less tolerant toward conspecifics, less sociable and more explorative were more likely to become dominant.