Interactions between lar gibbons and pig-tailed macaques at fruit sources


  • Claudia L. Whitington

    Corresponding author
    1. Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand
    • c/o Science Education Center, University of Texas at Austin, EDB 340, Austin, Texas 78712
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Interactions are reported between white-handed gibbons (Hylobates lar) and pig-tailed macaques (Macaca nemestrina) in Khao Yai National Park, Thailand, in which gibbons selected ripe fruit from sources before macaques arrived on 4 occasions during June and July of 1989. The macaques foraged near gibbons or from shared fruit sources during 13% of gibbon observation time. Gibbons made their presence known in fruit trees when macaques approached on 3 occasions and macaques did not enter fruit trees occupied by gibbons. An aggressive interaction is reported in which a single white-handed gibbon vigorously excluded 22–28 macaques from a rare and valuable fruit tree (Sandoricum koetjape). The observations suggest that exploitative and interference competition may exist between these species.