Agonistic Interactions in the Red Kangaroo (Megaleia rufa)

Two groups of red kangaroos composed of one male, a number of mature females, and some immature males and females were observed in captivity. From a detailed record of behavior, all agonistic approach-retreat interactions were extracted and analyzed as to the participants, initiator, and result. The results of all decisive encounters show that some animals were defeated by no others or only a few other animals, whereas some were defeated by most or all other animals in the group. A dominance hierarchy developed. Other aspects of agonistic behavior considered were aggression and success or the proportion of encounters in which an individual was dominant. There is agreement between ranks based on the outcome of paired encounters and on “success” scores. In each group, the highest ranking individuals were older and larger animals. Although stable social groups with a hierarchy of individuals may not exist in the field, a hierarchy of size or age classes is possible.