TY - JOUR
T1 - Meat sharing among the Gombe chimpanzees
T2 - Harassment and reciprocal exchange
AU - Gilby, Ian C.
N1 - Funding Information:
This project was funded by the L.S.B. Leakey Foundation, the Animal Behavior Society, Sigma Xi, the Explorers Club, the Dayton and Wilkie Natural History Funds, the University of Minnesota's Grants for Research Abroad Program and the Department of Ecology, Evolution and Behavior at the University of Minnesota. I thank the Tanzanian Commission for Science and Technology (COSTECH), the Tanzania Wildlife Research Institute (TAWIRI), Tanzania National Parks (TANAPA) and the Jane Goodall Institute for granting permission to conduct research at Gombe. Thanks also to Jane Goodall and Anne Pusey for providing access to the long-term Gombe data set. Anthony Collins and Shadrack Kamenya provided invaluable logistical help at Gombe, and Amri Almasi, Kadaha John and Iddi Issa were wonderful field assistants. Finally, I thank Lynn Eberly for statistical guidance and Anne Pusey, David Stephens, Jeff Stevens, Richard Wrangham, Carson Murray, Brian Wood and two anonymous referees for providing helpful comments on earlier versions of the manuscript. The research presented here was described under Animal Subject Codes Number 0005A52421, approved by the Institutional Animal Care and Use Committee of the University of Minnesota.
PY - 2006/4
Y1 - 2006/4
N2 - Sharing food with nonkin is detrimental to a food donor's fitness, unless it is matched by compensatory benefits. I evaluated two explanations for nonkin meat sharing among wild chimpanzees, Pan troglodytes schweinfurthii. Reciprocal exchange proposes that a possessor relinquishes food in exchange for past or future sharing or for items of a different currency (e.g. grooming, alliances or copulations). The second hypothesis is the sharing-under-pressure/harassment model, which proposes that an individual shares to avoid the costs of defending a food item against persistent beggars. At Gombe National Park, Tanzania, I collected dyadic grooming and association data during focal follows of adult male chimpanzees. I videotaped meat-eating bouts, subsequently extracting detailed begging and sharing data. There was mixed support for the reciprocal exchange hypothesis. Sharing with males was not influenced by overall association and grooming rates. Female sexual receptivity did not affect the probability of sharing, nor did sharing increase the probability of mating. Meat possessors shared larger amounts, and were more likely to share actively with frequent female grooming partners. However, this pattern may have resulted from increased harassment by these individuals. In contrast, the sharing-under- pressure hypothesis was consistently supported: the possessor's feeding rate decreased with the number of beggars, the probability of sharing increased with the occurrence and duration of harassment, and harassment decreased following sharing events. I conclude that the pattern of meat sharing among the Gombe chimpanzees is largely explained by the sharing-under-pressure hypothesis, while the significance of reciprocal exchange remains unclear.
AB - Sharing food with nonkin is detrimental to a food donor's fitness, unless it is matched by compensatory benefits. I evaluated two explanations for nonkin meat sharing among wild chimpanzees, Pan troglodytes schweinfurthii. Reciprocal exchange proposes that a possessor relinquishes food in exchange for past or future sharing or for items of a different currency (e.g. grooming, alliances or copulations). The second hypothesis is the sharing-under-pressure/harassment model, which proposes that an individual shares to avoid the costs of defending a food item against persistent beggars. At Gombe National Park, Tanzania, I collected dyadic grooming and association data during focal follows of adult male chimpanzees. I videotaped meat-eating bouts, subsequently extracting detailed begging and sharing data. There was mixed support for the reciprocal exchange hypothesis. Sharing with males was not influenced by overall association and grooming rates. Female sexual receptivity did not affect the probability of sharing, nor did sharing increase the probability of mating. Meat possessors shared larger amounts, and were more likely to share actively with frequent female grooming partners. However, this pattern may have resulted from increased harassment by these individuals. In contrast, the sharing-under- pressure hypothesis was consistently supported: the possessor's feeding rate decreased with the number of beggars, the probability of sharing increased with the occurrence and duration of harassment, and harassment decreased following sharing events. I conclude that the pattern of meat sharing among the Gombe chimpanzees is largely explained by the sharing-under-pressure hypothesis, while the significance of reciprocal exchange remains unclear.
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U2 - 10.1016/j.anbehav.2005.09.009
DO - 10.1016/j.anbehav.2005.09.009
M3 - Article
AN - SCOPUS:33645115243
SN - 0003-3472
VL - 71
SP - 953
EP - 963
JO - Animal Behaviour
JF - Animal Behaviour
IS - 4
ER -