Anthropological Science 107 (2), 141-188, 1999

AnthropologicalScience 107 (2), 141-188, 1999 Ethogram and Ethnography of Mahale Chimpanzees Toshisada Nishida1, Takayoshi Kano2, Jane Goodall3, William C. McGrew44, and Michio Nakamura1 1 Sub-Departmentof Anthropology,Graduate Schoolof Science,Kyoto University, Kyoto 2 Primate Research Institute, Kyoto University,Inuyama 3 Jane GoodallInstitute, Silver Spring, U.S.A. 4 Departments of Sociology,Gerontology and Anthropology,and of Zoology, Miami University, Oxford, U.S.A. (Submitted January 4, 1998; Review sent March 4, 1999; Accepted April 26, 1999) Abstract This paper aims to compile an exhaustive list of the behavioral patterns exhibited by the chimpanzees of the Mahale Mountains National Park, Tanzania. The compilation is based on the glossary compiled by Goodall (1989), but a substantial numbers of new terms have been added. Thus, we list 316 simple anatomical terms, 81 complex anatomical terms, 37 simple functional terms, and 81 complex functional terms, in addition to 116 synonyms. The behavioral patterns are divided into eight categories on the basis of degree of universality: (1) commonly seen in both Homo and two species of Pan, (1?) commonly seen in Homo and only one species of Pan, (2) patterns common to the genus Pan but not to Homo, (3) patterns common to the chimpanzee Pan troglodytes but not the bonobo Pan paniscus, (4) patterns common to eastern (P.t. schweinfurthii) and central (P.t. troglodytes) but not western (P.t. verus) chimpanzees, (5) patterns unique to the eastern chimpanzees, P.t. schweinfurthii, (6) patterns unique to the population of Mahale, (7) patterns unique to many individuals (at least most members of an age/sex class) of M group chimpanzees, (8) patterns limited to a single (idiosyncrasy) or a few individuals of M group. It is most likely that the behavior patterns of the last common ancestor of Homo and Pan are found in Categories 1 and 1? and less likely in Categories 2 and 3. It is possible that behavior patterns belonging to Categories 5, 6 or 7 are cultures. Keywords: ethogram, chimpanzee, Mahale Mountains, behavior, culture Corresponding author: Toshisada Nishida Sub-Department of Anthropology, Faculty of Science, Kyoto University Kitashirakawa-Oiwakecho, Sakyo, Kyoto, Japan TEL:+81-75-753-4084 FAX: +81-75-753-4098 E-mail: [email protected] 142 Nishida T., Kano T., Goodall J., McGrew W.C., and Nakamura M . Introduction This article aims to create an ethogram, that is, to list and describe all the behavioral patterns that have been recorded for the chimpanzees of the Mahale Mountains National Park, Tanzania. Previous such attempts only achieved a preliminary level of classification (Nishida, 1970; Mori, 1982). It is well known that chimpanzees show a great deal of local, as well as age, sex, and idiosyncratic, differences in behavior (for example, Goodall, 1973; Nishida , 1987; McGrew 1998). In which domains are the local behavioral differences most remarkable? This is an important question to be addressed if we want to solve the origins of human culture. The extent of local differences has not been well elucidated , partly because most of the study sites of chimpanzees lack a detailed ethogram. Gombe is an important exception: Goodall and her colleagues were pioneers in preparing a detailed glossary of the behavior of Gombe chimpanzees (Goodall, 1968, 1986, 1989; Bygott, 1974; Plooij, 1984). Consequently, it is relatively easy to compile a list of behavioral patterns of a local population by consulting the Gombe ethogram. A list of the behavioral patterns of a local population of the chimpanzees may in principle include (1) behavioral patterns of our last common ancestor of Pan and Homo, (2) patterns common to the genus Pan, namely chimpanzees and bonobos, but not to Homo, (3) patterns common to the chimpanzee Pan troglodytes , but not the bonobo Pan paniscus, (4) patterns common to eastern (P.t. schweinfurthii) and central (P.t. troglodytes), but not western (P.t. verus) chimpanzees, in view of the recent DNA cladistics (Morin and others, 1994), (5) patterns unique to the eastern chimpanzees, P. schweinfurthii, (6) patterns unique to the population of Mahale, (7) patterns unique to many individuals (at least most members of an age/sex class) of M group chimpanzees , (8) patterns limited to a single (idiosyncrasy) or a few individuals of M group. In addition, there are behavior patterns that we have found in both man and chimpanzees but not bonobos, as well as patterns common to both man and bonobos but not chimpanzees. These behavior patterns are either those of the last common ancestors of Pan and Homo, which either chimpanzee or bonobo has lost, or patterns that were lacking in the last common ancestor but evolved in both man and only one species of Pan in parallel after the split of chimpanzees and bonobos. The last possibility is less likely from the viewpoint of the parsimonious principle. Thus , we add Category 1? for these patterns whose status remain ambiguous. It is most likely that the behavior patterns of our last common ancestor are found in Categories 1 and 1? and less likely in Categories 2 and 3. Since little of the behavior of the chimpanzees of central Africa is known (Kuroda , 1998), it is impossible to delineate the Category (4) above . However, since there has been an increasing amount of information on west African chimpanzees, in particular those of the Tai Forest (for example, Boesch and Boesch, 1999), Bossou (Sugiyama, 1998; Matsuzawa and Yamakoshi, 1996), and Bossou and Kanka Sili' (Kortlandt and Bresser, 1963; Kortlandt and Kooij, 1963; Albrecht and Dunnett, 1971) , we can Ethogram of chimpanzees 143 tentatively regard the common patterns of eastern (Gombe and Mahale) and western (Tai) chimpanzees as candidates of behavior common to the species Pan troglodytes. Studies of the behavior patterns of humans (for example, Eibl-Eibesfeldt, 1972; McGrew, 1972; Morris, 1977) and bonobos (for example, Kano, 1980, 1992, 1998; Kuroda, 1980, 1984; Susman and others, 1980; de Waal, 1988) have been published, although to a lesser extent than studies on chimpanzees. Therefore, behavioral comparisons between chimpanzees, bonobos and humans can be made to some extent. Many authors have pointed out behavioral similarities and differences between humans and chimpanzees. Preliminary comparisons have already suggested interesting contrasts between chimpanzees and bonobos (for example, Mori, 1983; Nishida and Hiraiwa-Hasegawa , 1987; de Waal and Lanting, 1997). If we scrutinize the minute details of the behavioral patterns of these species, we might find many more differences between the two species. We need such comparisons in order to reconstruct the behavior of the last common ancestor of Homo and Pan. The class of behavioral category outlined above that each behavioral pattern belongs to cannot be elucidated before extensive research and comparison is made across many groups of local populations. However, a preliminary estimate can be made for some of the best known patterns. For example, no one would deny that "grooming" would be among the behavioral patterns of the last common ancestor. In such cases, we put "Category 1" , for example, in the last part of each behavioral pattern. Behavior patterns belonging to Categories 5, 6 or 7 are most likely to be cultures, but the status remains ambiguous until it is determined by careful comparison whether the environmental factors that might explain the local differences are present or absent. Methods In compiling an ethogram of Mahale chimpanzees, we tried to incorporate some new principles. First, we tried to make the ethogram maximally inclusive. Second, we distinguished functional definitions from "anatomical" ones. Elements of the latter should be provided for all functionally defined behavioral patterns. In order to attain this goal, we adopted the form of putting verbs in front of nouns or adjectives for the description of behavioral patterns. For example, we used "hunch bipedal" or "clip leaf" instead of "bipedal hunch" or "leaf -clip". Third , we made every effort to list the available references that had illustrations of behavioral patterns in the form of photographs, video frames, or drawings so that researchers at other study sites could verify whether the patterns they see are the same or different from the ones described by us. In order to classify behavioral patterns hierarchically and describe social relationships, both "anatomical" and functional terms are needed. This paper's major aim is to list names for all the behavioral elements in terms of anatomical details, but we also need functional terms in order to describe behavior that is meaningful in the natural habitat. For example, "approach" is a functional term. Although it is simply <walk> or <move> 144 Nishida T., Kano T., Goodall J., McGrew W.C., and Nakamura M. from the anatomical perspective, when one chimpanzee comes closer to another, some interaction will likely occur between them. Therefore, we must have a term "approach" in addition to <walk>, and so on. Moreover, from the perspective of cognitive psychology, we need functional terms. For example, a chimpanzee sometimes "detours", namely takes a long way round, avoiding, for example, an ill-tempered male who is sitting on a path. Detour is also simply <walk> or <move>. However, the term "detour" illustrates an important aspect of social cognition in that the chimpanzee predicts the associate's future behavior from experience and changes the travel route accordingly. Some behavior occurs as a sequence of different behavioral patterns or behavioral complexes; the "charging display" is an example of such a sequence. Some terms designate several morphologically distinct behavioral patterns that occur in similar contexts and have similar functions, although they may not occur simultaneously. Thus, we divide behavior patterns into four "Types": Type A is described by simple, anatomical terms such as "walk bipedal", Type B by complex anatomical terms such as "wrestle" , Type C by simple functional terms such as "approach", and Type D by complex functional terms such as "abuse".

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