Semi-wild chimpanzees open hard-shelled fruits differently across communities
- 413 Downloads
Researchers investigating the evolutionary roots of human culture have turned to comparing behaviours across nonhuman primate communities, with tool-based foraging in particular receiving much attention. This study examined whether natural extractive foraging behaviours other than tool selection differed across nonhuman primate colonies that had the same foods available. Specifically, the behaviours applied to open the hard-shelled fruits of Strychnos spp. were examined in three socially separate, semi-wild colonies of chimpanzees (Pan troglodytes) that lived under shared ecological conditions at Chimfunshi Wildlife Orphanage, and were comparable in their genetic makeup. The chimpanzees (N = 56) consistently applied six techniques to open these fruits. GLMM results revealed differences in the number of combined technique types to open fruits across the colonies. They also showed colony differences in the application of three specific techniques. Two techniques (full biting and fruit cracking) were entirely absent in some colonies. This study provides empirical evidence that natural hard-shelled fruit-opening behaviours are distinct across chimpanzee colonies, differences that most likely have not resulted from ecological and genetic reasons.
KeywordsChimpanzee Extractive foraging Hard-shelled fruits Culture Social learning
Special thanks go to Hannah Roome for helpful comments about the manuscript, to Daniela Hartmann for the reliability testing, and two anonymous reviewers for their helpful comments. M.D.-R. was funded by the European Commission’s FEELIX GROWING project (EC-FP6-IST-045169) and by the Psychology Department, University of Portsmouth. S.T.B was supported in part by a Leverhulme Trust Visiting Professorship, Department of Psychology, University of Portsmouth. We thank Sylvia Jones, Innocent Mulenga and Mark Bodamer for their hospitality and assistance with transportation while in Zambia, and would like to thank the founders of Chimfunshi, Sheila and David Siddle, for their tireless welfare efforts. M.D.-R. and B.R. designed this study, M.D.-R. collected data at the Chimfunshi Wildlife Orphanage (with help from S.T.B.), B.R. coded the observations and conducted the analysis (with help from M.D.R.), and B.R. and M.D.R. wrote the paper (with help from S.T.B).
- Bates D, Maechler M, Bolker B (2010) lme4: linear mixed effects models using S4 classes (R package version 0.999375-35). http://CRAN.R-project.org/package=lme4
- Goodall J (1986) The chimpanzees of Gombe: patterns of behaviour. Harvard University Press, CambridgeGoogle Scholar
- Mackinnon KC (2006) Food choice by juvenile capuchin monkeys Cebus capucinus in a tropical dry forest. Springer, New York. doi: 10.1007/0-387-25872-8_17
- Matsumoto-Oda A, Kasagula MB (2000) Preliminary study of feeding competition between baboons and chimpanzees in the Mahale Mountains National Park. Tanzania Af Stud Monogr 21:147–157Google Scholar
- McGrew WC (1979) Evolutionary implications of sex differences in chimpanzee predation and tool use. In: Hamburg DA, McCown E (eds). The Great Apes, Benjamin/Cummings Publishing, California, pp 441–463Google Scholar
- R Development Core Team (2010) R: a language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Rosenberger AL, Hartwig WC (2011) New world monkeys. Encyclopedia of life sciences, Nature Publishing Group. Macmillan Reference Ltd. http://www.els.net
- Tutin CEG, Baillie JEM, Dupain J., Gatti S, Maisels F, Stokes EJ, Morgan DB, Walsh PD (2008) Pan troglodytes ssp. troglodytes. In: IUCN 2013. IUCN Red List of Threatened SpeciesGoogle Scholar
- Wilson ML, Balmforth Z, Cox D, Davenport T, Hart J, Hicks C, Hunt KD, Kamenya S, Mitani JC, Moore J, Nakamura M, Nixon S, Plumptre AJ, Reynolds V (2008). Pan troglodytes ssp. schweinfurthii. In: IUCN 2013. IUCN red list of threatened speciesGoogle Scholar