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Introduction
Page 1
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Materials and Methods
Pages 2 - 3
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Discussion
Pages 8 - 9
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Conclusions
Page 10
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References
Page 11
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Figures 1- 8
Figures 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8
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Tables I-IV
Tables I - II - III - IV
(Continued from previous page)
Defense was not distinguished from offense by Van Hooff, except that he noted that some biting occurred as an "aggressive element that is most likely to be used by subordinate individuals in defense." Although the distinction between offense and defense is now becoming commonplace in studies of rodent behavior [Adams, 1979], it has not usually been made in observations of primates. Hall [1964] noted that dominant baboons attack subordinates by biting on the nape of the neck without producing any visible injury, while adult males engaged in fighting often received severe wounds around the face, shoulders, and rump. More recently, Owens [1975] has made similar observations in baboons and distinguished the two types of attack as "type 1" and "type 2" interactions.
The categories of submissive behavior, groom and contact, and male sexual behavior were similar in chimpanzee and stumptail. The stumptail's repertoire of facio-vocal activity during sex was more complex than that reported by Van Hooff, although he reports that chimpanzees sometimes engage in teeth chattering and lip smacking during sexual behavior in other situations [Van Hooff, 1973, p. 124].
The categories of bluff and excitement in the chimpanzee as described by Van Hooff [1973] may correspond to a set of behaviors that we may call "display" in the stumptail macaque. The acts of climbing, cage-shaking, and repeated bouncing have been associated in the Japanese macaque and called "display" by Modahl and Eaton [1977]. In the present study, along with patrol locomotion, they were found in association with the vocalization of barking, and they seemed to function particularly in dominant animals to display their potential for aggression. In the chimpanzee the acts and postures of "bluff" included arm-sway and stamp and their variants, the sway-walk and stamp-trot. As seen from Figure 44 in Van Hooff, these acts were associated with the vocalizations and expressions called "excitement," which include the rising hoot, grunt bark, and vertical head nod. Although climbing, cage-shaking, and patrolling were not described by Van Hooff, other authors such as Van Lawick-Goodall [1968] have described these behaviors during chimpanzee display behavior. Display behaviors, including patrolling, cage-climbing and shaking, barking and, perhaps, grunting were mimicked by two interacting animals. This mimickry has been noted in stumptail macaques by Bertrand [1969, p. 238] and is similar to mimickry of long-distance display calls in other primates [Waser, 1976].
Dominance is a quality that transcends the individual categories of behavior. In the present study it cut across and affected all of them; not only were defense, offense, and submission completely different in dominant and subordinate monkeys, but also there were important differences between them in grooming, display, and sexual behaviors. When groomed, the dominant animal was relaxed and sometimes would even lie down, whereas the subordinate animal, when groomed, remained in a tense posture, standing or sitting. In display sequences it was usually the dominant who initiated and the subordinate who imitated. Sexual behavior was different for dominants and subordinates. When mounting a subordinate, dominants were brisk and did not usually masturbate afterwards, whereas when they mounted another dominant the mounting was prolonged and followed by masturbation. Unlike the subordinate, however, they did not accompany their masturbation with the characteristic lip smacking and teeth chattering of sexual behavior.
The correspondence of the categories of behavior obtained by statistical analysis in the stumptail macaque and the chimpanzee is consistent with a motivational systems analysis. In comparing the stumptail macaque to the laboratory rat, it has been suggested that the following motivational systems could be found in adult males of both species: offense, defense, submission, male sex, and grooming [Adams, 1981]. Only one system, display, was found to be new in the primates. From the preceding discussion it would appear that these same systems are operational in the male chimpanzee, and that at least two other systems can be identified from the chimpanzee data, play and juvenile contact. Presumably they would be identified if one studied young stumptail macaques. The hypothesis that the same motivational systems operate in chimpanzees and stumptail macaques is consistent with the conclusion drawn from the rat/monkey comparison, that motivational systems are extremely conservative during the course of evolution. If this is correct, one might more safely assume that the same motivational systems would also operate in humans, although they would be modified by cultural factors and incorporated into the more complex units of institutionalized behavior.
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