Autoaggression and Tactile Communication in Pairs of Adult Stumptailed Macaques

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Abstract
Autoaggression (fighting behaviour directed to one's own body) is a trait quite commonly observed in captive macaques and is presumably induced by separate housing of the animals which prevents fighting between different individuals. Laboratory experiments in pairs of female stumptailed macaques noted for showing autoaggression were aimed at studying how the amount of time spent in autoaggression is affected by tactile interaction with a partner. Six different animals were used as subject as well as partner. Behaviour recording occurred during a subject's stay in the observation cage. Three experimental situations each lasting 15 minutes were used: t) tactile partner situation in which the partner was also present in the observation cage; v) visual partner situation: subject and partner were separated by a plexiglass sheet; n) no partner: the subject was alone. These situations were established during two immediately following observation periods so as to enable study of 1) effects of difference in immediate situation and 2) effects of difference in previous experience. Results showed that, during the tactile partner situation, the time spent in autoaggression was less than in the visual and no partner situations; the latter two did not differ consistently. The relatively small amount of autoaggression shown in the tactile situation was primarily due to the occurrence of allogrooming between subject and partner. There was no marked occurrence of alloaggression, so that there is no basis for the assumption that a shift from auto- to alloaggression is the primary cause of the relatively low level of autoaggression in the tactile partner situations. An effect on, i. e. a reduction of, the amount of time spent in autoaggression from having had an allogrooming experience was observed only in the situation in which the partner remained visually present. The present results suggest that prevention of allogrooming in separately housed macaques might also be a causal factor for development of autoaggression in captivity. In agreement with suggestions by others concerning the function of allogrooming in socially living monkeys, it might be that prevention of allogrooming abolishes suppression of aggression. Aggression is then directed to the subject's own body because fighting with another is also prevented. The fact that autoaggression continues to occur after tactile contact with partners is again possible suggests that it could also serve as avoiding the elicitation and receipt of social aggression. Autoaggression (fighting behaviour directed to one's own body) is a trait quite commonly observed in captive macaques and is presumably induced by separate housing of the animals which prevents fighting between different individuals. Laboratory experiments in pairs of female stumptailed macaques noted for showing autoaggression were aimed at studying how the amount of time spent in autoaggression is affected by tactile interaction with a partner. Six different animals were used as subject as well as partner. Behaviour recording occurred during a subject's stay in the observation cage. Three experimental situations each lasting 15 minutes were used: t) tactile partner situation in which the partner was also present in the observation cage; v) visual partner situation: subject and partner were separated by a plexiglass sheet; n) no partner: the subject was alone. These situations were established during two immediately following observation periods so as to enable study of 1) effects of difference in immediate situation and 2) effects of difference in previous experience. Results showed that, during the tactile partner situation, the time spent in autoaggression was less than in the visual and no partner situations; the latter two did not differ consistently. The relatively small amount of autoaggression shown in the tactile situation was primarily due to the occurrence of allogrooming between subject and partner. There was no marked occurrence of alloaggression, so that there is no basis for the assumption that a shift from auto- to alloaggression is the primary cause of the relatively low level of autoaggression in the tactile partner situations. An effect on, i. e. a reduction of, the amount of time spent in autoaggression from having had an allogrooming experience was observed only in the situation in which the partner remained visually present. The present results suggest that prevention of allogrooming in separately housed macaques might also be a causal factor for development of autoaggression in captivity. In agreement with suggestions by others concerning the function of allogrooming in socially living monkeys, it might be that prevention of allogrooming abolishes suppression of aggression. Aggression is then directed to the subject's own body because fighting with another is also prevented. The fact that autoaggression continues to occur after tactile contact with partners is again possible suggests that it could also serve as avoiding the elicitation and receipt of social aggression.