One Good Turn Deserves Another: Combat versus Other Functions of Acrobatic Maneuvers in the Play Fighting of Vervet Monkeys (Chlorocebus aethiops)

Abstract

During play fighting, animals make a variety of movements, some of which seem unrelated to the ongoing actions of the partner. Among such movements are the jumps and rotations reported in many species of Old World monkeys. In the present study, videotaped sequences of jumps and rotations performed by juvenile vervet monkeys were analyzed. Using the Eshkol-Wachman Movement Notation (EWMN) the sequences were described frame-by-frame revealing that about 82% of the jumps and rotations were correlated with the movements performed by the partner, consistent with the view that these movements are used as tactics of attack and defense. The majority of the remaining 18% occurred in contexts in which the performer solicited playful attacks from the partner. A small number of the rest were performed in a manner consistent with the movements being imposed by the performer to increase the difficulty in contacting the partner. The same distribution was present in both captive and free-living monkeys. Thus the analyses show that while most jumps were combat-related, these movements can occur in a variety of functional contexts.