Date of Award
Master of Science
Ecology and Evolutionary Biology
Gordon Burghardt, Christine Boake
It is widely accepted that providing stimulus enrichment and opportunities to play is an important part of the development and maintenance of behavior and well-being in mammals. However, extending this idea to non-avian reptiles has barely been explored Observations reported by scientists, zookeepers, and others, however, have suggested that non-avian reptiles can and do perform some form of play and exploration with novel objects and may benefit from enriched environments. Varanids display several advanced mammalian-like characteristics (i.e. physiology, life history, and prey discrimination) compared to other reptiles, and it is plausible that higher cognitive behaviors are also present. It was hypothesized that play and exploratory behaviors would be exhibited in the these trials and that the monitors would react differently to each stimulus. This study, based on systematic videotaped trials, analyzed the behaviors of eight juvenile Blackthroated monitors, Varanus albigularis, in response to an enriched environment. Two objects (food ball and food tube) and one social stimulus were introduced. The food ball allowed the monitors to see and smell, but not attain, the prey while the food tube allowed the monitors to attain the prey through hinged doors. In the social introductions the monitors could see and smell, but had no physical contact with, a conspecific placed in their home enclosure. After constructing a behavioral inventory based on the videotapes, the mean duration and mean occurrence of various state and event behaviors were analyzed. There were many significant differences in the amount and type of behavior patterns elicited (p<0.009) by the different types of stimuli introduced. Responses to the food ball exhibited the most change over time and primarily consisted of exploratory and play-like behaviors after the predatory responses declined. However, this stimulus was presented the most times (10). Responses to the food tube were primarily predatory behaviors and the lizards showed learning in opening the tube and capturing the prey by the second trial. Finally the conspecific elicited social behaviors that were not seen in the other two treatments such as a rocking seesaw behavior. These results suggest these animals are interactive, discriminating, and exploratory. This study provides further evidence for the need for more in depth enrichment, specifically object introductions, in captive non-avian reptiles. The responses seen in captivity can lead us to reassess behavior reported in wild monitors, as well as to look for more affiliative social behavior and novel foraging tactics. Due to the results of this and similar studies, serious consideration should be given to providing enrichment in captive squamate reptiles in general, and large long-lived species in particular.
Manrod, Jennifer Diane Walton, "Object introduction, exploration, and play behavior in Black-throated monitor lizards (Varanus albigularis albigularis). " Master's Thesis, University of Tennessee, 2003.