Date of Award


Honors Thesis Number




Faculty Advisor

Waring, George H.


An ethological investigation was made on a group of western lowland gorillas (Gorilla gorilla gorilla) at the Lincoln Park Zoo, Chicago. Focal animal sampling and all-occurrences sampling were used to collect data during the months of June and July 2000. Qualitative observations were made of the general behavioral patterns of the group, which included feeding and drinking behavior, resting, sleeping, nest construction, grooming behavior, group behavior, dominance hierarchies, zoo-keeper and public oriented behavior, and behavior in novel stimuli situations. Except for female dominance hierarchies, all behavioral patterns were found to be similar to those reported for feral gorillas. The primary focus of this study was on play behavior in infant western lowland gorillas. Play was categorized into three types: solitary play, social play, and mother-infant play. In my study group, age, gender, and type of rearing had no influence on the percentage of time spent by each individual in these three play categories. All of the infants spent most of their time engaged in solitary play and social play. Mother-infant play was found to be almost non-existent by the time a gorilla infant reached two years of age. Social play peaked during the early afternoon and consisted mainly of contact play. Infants spent a greater amount of time engaged in object play, as compared to locomotor and self-directed play.