Behavioral Ecology and Sociobiology

, Volume 61, Issue 11, pp 1771–1779 | Cite as

Risk-prone hunting by chimpanzees (Pan troglodytes schweinfurthii) increases during periods of high diet quality

Original Paper

Abstract

Most studies suggest that during times of nutritional stress, an animal faced with two foraging choices should follow a risk-prone strategy, choosing the option with highest payoff variance. This “scarcity/risk” hypothesis was developed to account for the foraging patterns of small animals with high metabolic rates susceptible to the threat of starvation. In this paper, we propose that animals should also be risk-prone when their diet quality is particularly high, far exceeding that which is needed to survive. Under these circumstances, the costs of experiencing a low or negative payoff can easily be recouped. We suggest that large-bodied omnivores are most likely to adopt this “abundance/risk” strategy. We investigate this question among wild chimpanzees (Pan troglodytes) that choose between a risk-averse strategy of feeding on plant material and a risk-prone strategy of hunting red colobus monkeys. Using 14 years of data on the Kanyawara chimpanzees of Kibale National Park, Uganda, we find strong evidence that chimpanzees follow the “abundance/risk” strategy. Both hunting rate (hunts/100 observation hours) and the probability of hunting upon encountering red colobus monkeys were positively correlated with seasonal consumption of ripe drupe fruits, a class of preferred food associated with elevated reproductive performance by females. Critically, these results remained statistically significant after controlling for the potentially confounding effects of male chimpanzee party size and the presence of sexually receptive females. These findings suggest that the relationship between risk-sensitive foraging and diet quality depends upon the daily probability of starvation, the number of alternative foraging strategies, and the degree to which diet quality satisfies an animal’s nutritional requirements.

Keywords

Chimpanzee Hunting Risk-sensitive foraging Diet quality 

References

  1. Altmann J (1974) Observational study of behavior: sampling methods. Behaviour 49:227–267PubMedGoogle Scholar
  2. Anderson DP, Nordheim EV, Boesch C, Moermond TC (2002) Factors influencing fission–fusion grouping in chimpanzees in the Taï National Park, Côte d’Ivoire. In: Boesch C, Hohmann G, Marchant L (eds) Behavioural diversity in chimpanzees and bonobos. Cambridge University Press, Cambridge, pp 90–101Google Scholar
  3. Bateson M (2002) Recent advances in our understanding of risk-sensitive foraging preferences. Proc Nutr Soc 61:509–516PubMedCrossRefGoogle Scholar
  4. Bateson M, Kacelnik A (1998) Risk-sensitive foraging: decision making in variable environments. In: Dukas R (ed) Cognitive ecology. Chicago University Press, Chicago, IL, pp 297–341Google Scholar
  5. Boesch C, Boesch H (1989) Hunting behavior of wild chimpanzees in the Taï National Park. Am J Phys Anthropol 78:547–573PubMedCrossRefGoogle Scholar
  6. Boesch C, Boesch-Achermann H (2000) The chimpanzees of the Taï Forest. Behavioural ecology and evolution. Oxford University Press, OxfordGoogle Scholar
  7. Busse CD (1977) Chimpanzee predation as a possible factor in the evolution of red colobus monkey social organization. Evolution 31:907–911CrossRefGoogle Scholar
  8. Caraco T, Blanckenhorn WU, Gregory GM, Newman JA, Recer GM, Zwicker SM (1990) Risk-sensitivity: ambient temperature affects foraging choice. Anim Behav 39:338–345CrossRefGoogle Scholar
  9. Cartar RV, Dill LM (1990) Why are bumblebees risk sensitive foragers? Behav Ecol Sociobiol 26:121–127CrossRefGoogle Scholar
  10. Chapman CA, Fedigan LM (1990) Dietary differences between neighboring Cebus capuchinus groups: local traditions, food availability or responses to food profitability? Folia Primatol 54:177–186PubMedGoogle Scholar
  11. Chapman CA, White FJ, Wrangham RW (1994) Party size in chimpanzees and bonobos: a re-evaluation of theory based on two similarly forested sites. In: Wrangham RW, McGrew WC, de Waal FBM, Heltne PG (eds) Chimpanzee cultures. Harvard University Press, Cambridge, MA, pp 41–57Google Scholar
  12. Chapman CA, Wrangham RW, Chapman LJ (1995) Ecological constraints on group size: an analysis of spider monkey and chimpanzee subgroups. Behav Ecol Sociobiol 36:59–70CrossRefGoogle Scholar
  13. Conklin-Brittain NL, Wrangham RW, Hunt KD (1998) Dietary response of chimpanzees and cercopithecines to seasonal variation in fruit abundance. II. Macronutrients. Int J Primatol 19:971–998CrossRefGoogle Scholar
  14. Croy MI, Hughes RN (1991) Effects of food supply, hunger, danger and competition on choice of foraging location by the fifteen-spined stickleback, Spinachia spinachia. Anim Behav 42:131–139CrossRefGoogle Scholar
  15. Emery Thompson M (2005) Endocrinology and ecology of wild female chimpanzee reproduction. Ph.D. thesis, Department of Anthropology, Harvard University, CambridgeGoogle Scholar
  16. Emery Thompson M, Wrangham RW (2006) Comparison of sex differences in gregariousness in fission–fusion species: reducing bias by standardizing for party size. In: Newton-Fisher NE, Notman H, Paterson JD, Reynolds V (eds) Primates of Western Uganda. Springer, New York, pp 209–226Google Scholar
  17. Fedigan LM (1990) Vertebrate predation in Cebus capuchinus: meat eating in a neotropical monkey. Folia Primatol 54:196–205PubMedCrossRefGoogle Scholar
  18. Gilby IC (2004) Hunting and meat sharing among the chimpanzees of Gombe National Park, Tanzania. Ph.D. thesis, University of MinnesotaGoogle Scholar
  19. Gilby IC, Eberly LE, Pintea L, Pusey AE (2006) Ecological and social influences on the hunting behaviour of wild chimpanzees (Pan troglodytes schweinfurthii). Anim Behav 72:169–180CrossRefGoogle Scholar
  20. Goodall J (1986) The chimpanzees of Gombe: patterns of behavior. Harvard University Press, Cambridge, MAGoogle Scholar
  21. Kacelnik A, Bateson M (1996) Risky theories—the effects of variance on foraging decisions. Am Zool 36:402–434Google Scholar
  22. Kissui BM, Packer C (2004) Top-down population regulation of a top predator: lions in the Ngorongoro Crater. Proc R Soc Lond B Biol Sci 271:1867–1874CrossRefGoogle Scholar
  23. Matsumoto-Oda A (1999) Mahale chimpanzees: grouping patterns and cycling females. Am J Primatol 47:197–207PubMedCrossRefGoogle Scholar
  24. Matsumoto-Oda A, Hosaka K, Huffman MA, Kawanaka K (1998) Factors affecting party size in chimpanzees of the Mahale mountains. Int J Primatol 19:999–1011CrossRefGoogle Scholar
  25. Milton K (2003) The critical role played by animal source foods in human (Homo) evolution. J Nutr 133:3886S–3892SPubMedGoogle Scholar
  26. Mitani JC, Watts DP (2001) Why do chimpanzees hunt and share meat? Anim Behav 61:915–924CrossRefGoogle Scholar
  27. Mitani JC, Watts DP (2005) Seasonality in hunting by non-human primates. In: Brockman DK, van Schaik CP (eds) Seasonality in primates: studies of living and extinct human and non-human primates. Cambridge University Press, Cambridge, pp 215–240Google Scholar
  28. Mitani JC, Watts DP, Lwanga JS (2002) Ecological and social correlates of chimpanzee party size and composition. In: Boesch C, Hohmann G, Marchant L (eds) Behavioural diversity in chimpanzees and bonobos. Cambridge University Press, Cambridge, pp 102–111Google Scholar
  29. Nevin OT, Gilbert BK (2005) Measuring the cost of risk avoidance in brown bears: further evidence of positive impacts of ecotourism. Biol Conserv 123:453–460CrossRefGoogle Scholar
  30. Nishida T (1968) The social group of wild chimpanzees in the Mahali mountains. Primates 9:167–224CrossRefGoogle Scholar
  31. Nishida T, Uehara S, Nyundo R (1979) Predatory behavior among wild chimpanzees of the Mahale mountains. Primates 20:1–20CrossRefGoogle Scholar
  32. Odonoghue M, Boutin S, Krebs CJ, Hofer EJ (1997) Numerical responses of coyotes and lynx to the snowshoe hare cycle. Oikos 80:150–162CrossRefGoogle Scholar
  33. Pontzer H, Wrangham RW (2004) Climbing and the daily energy cost of locomotion in wild chimpanzees: implications for hominoid locomotor evolution. J Hum Evol 46:317–335PubMedCrossRefGoogle Scholar
  34. Pusey AE, Oehlert GW, Williams JM, Goodall J (2005) Influence of ecological and social factors on body mass of wild chimpanzees. Int J Primatol 26:3–31CrossRefGoogle Scholar
  35. Rose LM (1997) Vertebrate predation and food-sharing in Cebus and Pan. Int J Primatol 18:727–765CrossRefGoogle Scholar
  36. Sherry DN (2002) Reproductive seasonality in chimpanzees and humans: ultimate and proximate factors. Ph.D. thesis, Harvard University, Cambridge, MAGoogle Scholar
  37. Stanford CB (1995) The influence of chimpanzee predation on group size and anti-predator behaviour in red colobus monkeys. Anim Behav 49:577–587Google Scholar
  38. Stanford CB (1998) Chimpanzee and red colobus. Harvard University Press, Cambridge, MassachusettsGoogle Scholar
  39. Stanford CB, Wallis J, Mpongo E, Goodall J (1994) Hunting decisions in wild chimpanzees. Behaviour 131:1–18Google Scholar
  40. Stephens DW (1981) The logic of risk-sensitive foraging preferences. Anim Behav 29:628–629CrossRefGoogle Scholar
  41. Takahata Y, Hasegawa T, Nishida T (1984) Chimpanzee predation in the Mahale mountains from August 1979 to May 1982. Int J Primatol 5:213–233Google Scholar
  42. Uehara S (1997) Predation on mammals by the chimpanzee (Pan troglodytes). Primates 38:193–214CrossRefGoogle Scholar
  43. Wallis J (1997) A survey of reproductive parameters in the free-ranging chimpanzees of Gombe National Park. J Reprod Fertil 109:297–307PubMedCrossRefGoogle Scholar
  44. Watts DP, Mitani JC (2002a) Hunting and meat sharing by chimpanzees at Ngogo, Kibale National Park, Uganda. In: Boesch C, Hohmann G, Marchant L (eds) Behavioural diversity in chimpanzees and bonobos. Cambridge University Press, Cambridge, pp 244–255Google Scholar
  45. Watts DP, Mitani JC (2002b) Hunting behavior of chimpanzees at Ngogo, Kibale National Park, Uganda. Int J Primatol 23:1–28CrossRefGoogle Scholar
  46. Wilson ML (2001) Imbalances of power: how chimpanzees respond to the threat of intergroup aggression. Ph.D. thesis, Harvard University, Cambridge, MAGoogle Scholar
  47. Wrangham RW (1977) Feeding behaviour of chimpanzees in Gombe National Park, Tanzania. In: Clutton-Brock TH (ed) Primate ecology: studies of feeding and ranging behaviour in lemurs, monkeys and apes. Academic, London, pp 503–538Google Scholar
  48. Wrangham RW (2000) Why are male chimpanzees more gregarious than mothers? A scramble competition hypothesis. In: Kappeler PM (ed) Primate males: causes and consequences of variation in group composition. Cambridge University Press, Cambridge, pp 248–258Google Scholar
  49. Wrangham RW (2002) The cost of sexual attraction: is there a trade-off in female Pan between sex appeal and received coercion? In: Boesch C, Hohmann G, Marchant L (eds) Behavioural diversity in chimpanzees and bonobos. Cambridge University Press, Cambridge, pp 204–215Google Scholar
  50. Wrangham RW, Smuts B (1980) Sex differences in the behavioral ecology of chimpanzees in the Gombe National Park, Tanzania. J Reprod Fertil (Suppl) 28:13–31Google Scholar
  51. Wrangham RW, Conklin NL, Chapman CA, Hunt KD (1991) The significance of fibrous foods for Kibale Forest chimpanzees. Philos Trans R Soc B 334:171–178CrossRefGoogle Scholar
  52. Wrangham RW, Chapman CA, Clark-Arcadi AP, Isabirye-Basuta G (1996) Social ecology of Kanyawara chimpanzees: implications for understanding the costs of great ape groups. In: Nishida T (ed) Great ape societies. Cambridge University Press, Cambridge, pp 45–57Google Scholar
  53. Wrangham RW, Conklin-Brittain NL, Hunt KD (1998) Dietary response of chimpanzees and cercopithecines to seasonal variation in fruit abundance: I. Antifeedants. Int J Primatol 19:949–970CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  1. 1.Department of AnthropologyHarvard UniversityCambridgeUSA

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