Primate Research
Online ISSN : 1880-2117
Print ISSN : 0912-4047
ISSN-L : 0912-4047
Volume 37, Issue 1
Displaying 1-33 of 33 articles from this issue
Preface
Original Article
  • Yukino SAWA, Toru OI
    2021 Volume 37 Issue 1 Pages 5-15
    Published: 2021
    Released on J-STAGE: July 01, 2021
    Advance online publication: June 01, 2021
    JOURNAL FREE ACCESS

    Japanese macaques (Macaca fuscata) raid villages to obtain crops and other foods, such as the fruit of abandoned persimmon trees, fallen rice ears, second growth of rice, and other crop residues that are of no value to humans but can attract macaques and cause them to settle near villages. This study quantified the effects of persimmons and unplowed paddies after harvest that supply second growth of rice and herbs as food for raiding macaques. We observed the Kurodani A macaque group in Ishikawa Prefecture in the autumn of 2019. The number of persimmons decreased rapidly from the second half of October to the first half of November and decreased moderately after that. After harvesting paddies, the area of unplowed paddies decreased moderately from its peak in the first half of October. After October, the macaque group spent 30~40% of its daily activity time in villages and farmlands, forging mainly for persimmons, chestnuts, rice ears, and herbs. The group raided five or six villages until the first half of November, but after the second half of November it mainly raided two villages where most of the persimmons and unplowed paddies remained. Analysis using a generalized linear mixed model suggested that the number of persimmons and area of unplowed paddies significantly influenced raiding by the group. As countermeasures against raiding by Japanese macaque groups, we recommend removing any persimmons and plowing paddies after harvest.

    Download PDF (4261K)
Research Report
  • Naofumi NAKAGAWA
    2021 Volume 37 Issue 1 Pages 17-34
    Published: 2021
    Released on J-STAGE: July 01, 2021
    Advance online publication: June 01, 2021
    JOURNAL FREE ACCESS
    Supplementary material

    A web-based questionnaire of infrequently observed behaviors (IOBs) in Japanese macaques (Macaca fuscata) referring to their video footage is administered to primatologists. The first aim was to confirm that the questionnaire methodology had improved relative to that of conventional paper-based questionnaire. The main aim is to extract inter-population differences that could be considered cultural by focusing on IOBs that can be seen in one population but not in another. Participants were asked to report whether they had observed 99 candidate IOBs by answering “yes,” “no,” or “impossible to answer because of ambiguous memory or lack of awareness of the behavior.” In total, 62 answer sheets were returned. As expected, the percentage of “impossible to answer because of lack of awareness” among all respondents decreased due to the use of video footage. Following the percentage of respondents answering “yes” to all giving definite answers (“yes” or “no”), each population was classified as frequently seen (100% ≥ p > 75%), seen (75% ≥ p > 0%), or never seen (0%). The behaviors that were seen in only one population but never seen in others cannot be called cultural yet, as they are not likely to have spread to an extent that could be considered habitual; instead, they should be regarded as innovations of behavior. The following behaviors were extracted: rump–rump contact between males, detachment of branches for branch-dragging social play, and pulling the hair of a female’s chin as courtship by a male. Behaviors that were never seen in at least one but were frequently seen in at least one population, and seen in others, and cannot be explained by environmental differences, can be considered cultural. The following behaviors were extracted: embracing behaviors and stone-handling, both of which have known cultural variations, as well as spitting allo-grooming, spitting self-grooming, self-wrist biting, and breaking-bubbles solo play.

    Download PDF (1284K)
Review
  • Shintaro ISHIZUKA
    2021 Volume 37 Issue 1 Pages 35-46
    Published: June 20, 2021
    Released on J-STAGE: July 01, 2021
    Advance online publication: June 01, 2021
    JOURNAL FREE ACCESS

    Little is known about the social systems of primates at the local population level. For a better understanding of the matter, African great apes are appropriate subjects because many studies have investigated multiple neighboring groups. Here, I reviewed patterns of dispersal, extra-group paternity, and intergroup relationships in African great apes. These three topics are relevant to the three components of primate social systems defined by Kappeler & van Schaik (2002): social organization, mating system, and social structure, respectively. Patterns of female dispersal are similar among African great apes, in that females usually immigrate into groups near their natal groups. In contrast, patterns of male dispersal, often observed in gorillas, are more variable; some males stay near their natal groups after dispersal while others disperse far from their natal groups. Extra-group paternity is rare in African great apes. This is likely because males actively guard females against extra-group males due to severe male-male reproductive competition. Furthermore, extra-group paternity is considered to be disadvantageous in male-philopatric species, as it weakens the degree of kinship among philopatric males within groups. Intergroup male-male relationships are typically antagonistic due to resource defense, although male gorillas sometimes show high degrees of tolerance toward extra-group males. In contrast, intergroup female-female relationships are much more tolerant and affinitive, likely because females typically remain near their natal groups even after dispersal, so that females of neighboring groups are sometimes related to each other. This review highlights that dispersal in both sexes and a scarcity of intergroup breeding shape the kin structure of local populations, which contributes to regulating intergroup relationships in African great apes. Future behavioral and genetic studies that target multiple neighboring groups and dispersing individuals are required to further develop our understanding of primate societies at the local population level.

    Download PDF (1004K)
Information
Other
Information
Book Reviews
Announcement from the Executive Board
Conservation
Proceedings of the 36th Annual Meeting of PSJ
Highlight of the Papers in Primates
feedback
Top