Michio Nakamura

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Observations of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) provide valuable comparative data for understanding the significance of conspecific killing. Two kinds of hypothesis have been proposed. Lethal violence is sometimes concluded to be the result of adaptive strategies, such that killers ultimately gain fitness benefits by increasing(More)
Chimpanzees (Pan troglodytes) often groom in gatherings that cannot simply be divided into unilateral dyadic grooming interactions. This feature of grooming is studied at two different levels: grooming cliques and grooming clusters. Grooming cliques are defined as directly connected configurations of grooming interactions at any given moment, and when any(More)
Here we consider the concept of kaluchua (a word adopted from the English "culture") in group-living animals developed by Imanishi in the 1950s. He distinguished it from bunka (the Japanese equivalent to the English "culture") because he thought that bunka had strong connotations of noble and intellectual human-like activities. Although he did not rigidly(More)
Use of leaves or sticks for drinking water has only rarely been observed during long-term study of wild chimpanzees (Pan troglodytes schweinfurthii) at Mahale. Recently, however, we observed 42 episodes of tool-use for drinking water (73 tools and two cases of using "tool-sets") between 1999 and 2004. Interestingly, all of the performers were immature(More)
The purpose of this study is to compare the efficacy of a single administration of dexamethasone (DEX) on day 1 against DEX administration on days 1-3 in combination with palonosetron (PALO), a second-generation 5-HT3 receptor antagonist, for chemotherapy-induced nausea and vomiting (CINV) in non-anthracycline and cyclophosphamide (AC) moderately-emetogenic(More)
Toshisada Nishida, a pioneer in the study of primate behavior, died on June 7, 2011 following a prolonged battle with cancer. He was 70 years old. Nishida began his career while still an undergraduate student at Kyoto University, where he was inspired by Kinji Imanishi. In 1962, he investigated interactions between two groups of Formosan macaques that had(More)
We report the physical and behavioral development of one severely disabled female infant chimpanzee (Pan troglodytes schweinfurthii) of the well-habituated M group in the Mahale Mountains National Park. We documented interactions between the infant and its mother and with other group members. Congenital disabilities occur in many primate species, including(More)
Great apes are important seed dispersers with large bodies, able to swallow large seeds and travel long distances. Although there have been several studies investigating seed dispersal quality [sensu Schupp (Vegetatio 107/108:15–29, 1993)] by chimpanzees, there is little information on the volume of seeds they can carry in their bodies. When a relatively(More)
sion has been well documented as coalitionary behavior may be an evolved tactic by which chimpanzees increase their fitness through increased access to territory, food and mates (Watts & Mitani 2001; Wilson & Wrangham 2003; Watts et al. 2006; Wrangham et al. 2006). That the pattern holds for intracommunity aggression suggests that ecology and territory size(More)
Among cultural behaviors of chimpanzees, the developmental processes of complex skills involved in tool use are relatively well known. However, few studies have examined the ontogeny of social customs that do not require complex skills. Thus, in this study, we describe the developmental process of the grooming hand-clasp (GHC), one of the well-known social(More)