Diet and Food Choice in Peruvian Red Uakaris (Cacajao calvus ucayalii): Selective or Opportunistic Seed Predation?



Even primates considered dietary specialists tend to eat a combination of fruit pulp, seeds, other plant parts, or animals. Specialist seed predators could either feed on seeds preferentially, or to avoid competition when ripe pulps are scarce. Pitheciin monkeys have specialized dentition that allows them to feed on seeds protected by hard shells, and the upper limit on the hardness of these is likely to be a function of jaw size. We recorded the diet of Peruvian red uakaris (Cacajao calvus ucayalii) on the Yavari River, Peru, to test the prediction that this seed predator would feed on the seeds of hard-shelled fruits preferentially over softer ones in relation to their availability in the forest. We also tested predictions that adult male, adult female, and juvenile diets would differ, with larger individuals eating more hard fruits. Uakaris ate 55.4% seeds, 38.9% pulps and arils, and 5.6% other items, but proportions varied through the year. More pulps, especially from the palm Mauritia flexuosa, were eaten when fruit availability was low, and more hard fruits were positively selected for than softer ones. Juveniles did not open the hardest fruit species opened by adults, and adult males ate harder fruits than females. These results provide evidence that seed eating in some primates has evolved beyond a means of avoiding competition for the ripe pulps typically preferred by many primates. Specialist seeding-eating primates therefore occupy divergent niches that require separate consideration from those of similar-sized primates.


Cacajao Diet Pitheciin Pitheciini Uacari Uakari 



Data collection was funded by Rufford Small Grants, LA Zoo, Conservation International, Primate Conservation Inc. and was supported logistically by the Wildlife Conservation Society and the Earthwatch Institute. We collected data with a permit from INRENA (Instituto Nacional de Recursos Naturales) of the Peruvian government, and the methodology complied with their regulations. Botanists Corine Vriesendorp, Marco Rios, Ricardo Zarate, and Robin Foster identified trees and fruits in the field and from samples and photographs, and Alfonso Mendez and Olivia Curno were indispensable in their help with the fruit transects. We thank WCS and DICE, Pablo Puertas, Miguel Antunez, Pedro Perez, Maribel Recharte, Paddy Brock, the boat crews of Amazoneco, field assistants of WCS, and the people of Carolina and Nuevo Esperanza. We especially thank Gurdun Sperrer and the Pilpintuwasi Amazon Animal Orphanage, Iquitos for their participation in our research. We thank Blake Morton for his comments on a draft of this article, and Jessica Rothman and 2 anonymous referees whose comments greatly improved the manuscript.

Supplementary material

10764_2011_9527_MOESM1_ESM.docx (72 kb)
Table SI (DOCX 71 kb)


  1. Altmann, J. (1974). Observational study of behaviour: Sampling methods. Behaviour, 48, 1–41.CrossRefGoogle Scholar
  2. Aquino, R. (1995). Concervación de Cacajao calvus ucayalii en la Amazonia Peruana. Neotropical Primates, 3, 40–42.Google Scholar
  3. Aquino, R., & Encarnación, F. (1999). Observaciónes preliminares sobre la dieta de Cacajao calvus ucayalii en el Nor-Oriente Peruano. Neotropical Primates, 7, 1–5.Google Scholar
  4. Ayres, J. M. (1986). The white Uakaris and the Amazonian flooded forests. Ph.D. thesis, University of Cambridge.Google Scholar
  5. Ayres, J. M. (1989). Comparative feeding ecology of the uakari and bearded saki, Cacajao and Chiropotes. Journal of Human Evolution, 18, 697–716.CrossRefGoogle Scholar
  6. Barnett, A. A., de Castilho, C. V., Shapley, R. L., & Anicácio, A. (2005). Diet, habitat selection, and natural history of the golden-backed uacari, Cacajao melanocephalus ouakary, in Jaú National Park, Brazil. International Journal of Primatology, 26, 961–981.CrossRefGoogle Scholar
  7. Barton, R. A., & Whiten, A. (1994). Reducing complex diets to simple rules: Food selection by olive baboons. Behavioral Ecology and Sociobiology, 35, 283–293.CrossRefGoogle Scholar
  8. Boubli, J. P. (1999). Feeding ecology of black-headed uakaris (Cacajao melanocephalus melanocephalus) in the Pico de Neblina National Park, Brazil. International Journal of Primatology, 20, 719–749.CrossRefGoogle Scholar
  9. Bowler, M., & Bodmer, R. E. (2009). Social behavior in fission–fusion groups of red uakari monkeys (Cacajao calvus ucayalii). American Journal of Primatology, 71, 976–987.PubMedCrossRefGoogle Scholar
  10. Buchanan, D. B., Mittermeier, R. A., & van Roosmalen, M. G. M. (1981). The saki monkeys, genus Pithecia. In A. F. Coimbra-Filho & R. A. Mittermeier (Eds.), Ecology and behaviour of Neotropical primates (pp. 391–417). Rio de Janeiro: Academia Brasileira de Ciencias.Google Scholar
  11. Cunningham, E. P., & Janson, C. H. (2006). Pithecia pithecia’s behavioral response to decreasing fruit abundance. American Journal of Primatology, 68, 491–497.PubMedCrossRefGoogle Scholar
  12. Dasilva, G. L. (1994). Diet of Colobus polykomos on Tiwai Island: Selection of food in relation to its seasonal abundance and nutritional quality. International Journal of Primatology, 15, 655–680.CrossRefGoogle Scholar
  13. Fischer, K. E., & Chapman, C. A. (1993). Frugivores and fruit syndromes: Differences in patterns at the genus and species level. Oikos, 66, 472–482.CrossRefGoogle Scholar
  14. Fontaine, R. (1981). The uakaris, genus Cacajao. In A. F. Coimbra-Filho & R. A. Mittermeier (Eds.), Ecology and behaviour of Neotropical primates. Rio de Janeiro: Academia Brasileira de Ciencias.Google Scholar
  15. Heiduck, S. (1997). Food choice in masked titi monkeys (Callicebus personatus melanochir): Selectivity or opportunism? International Journal of Primatology, 18, 487–502.CrossRefGoogle Scholar
  16. Hemingway, C. A. (1998). Selectivity and variability in the diet of Milne-Edwards’ sifakas (Propithecus diadema edwardsi): Implications for folivory and seed-eating. International Journal of Primatology, 19, 355–377.CrossRefGoogle Scholar
  17. Hershkovitz, P. (1987). Uacaries, New World monkeys of the genus Cacajao (Cebidae, Platyrrhini): A preliminary taxonomic review with the description of a new subspecies. American Journal of Primatology, 12, 1–53.CrossRefGoogle Scholar
  18. Ivlev, V. S. (1961). Experimental ecology of the feeding of fishes. New Haven: Yale University Press.Google Scholar
  19. Johns, A. (1986). Notes on the ecology and current status of the buffy saki, Pithecia albicans. Primate Conservation, 7, 26–29.Google Scholar
  20. Kay, R. F., Plavcan, J. M., Glander, K. E., & Wright, P. C. (1988). Sexual selection and canine dimorphism in New World monkeys. American Journal of Physical Anthropology, 77, 385–397.PubMedCrossRefGoogle Scholar
  21. Kinzey, W. G. (1992). Dietary and dental adaptations in the Pitheciinae. American Journal of Physical Anthropology, 88, 499–514.PubMedCrossRefGoogle Scholar
  22. Kinzey, W. G., & Norconk, M. A. (1990). Hardness as a basis of fruit choice in two sympatric primates. American Journal of Physical Anthropology, 81, 5–15.PubMedCrossRefGoogle Scholar
  23. Kinzey, W. G., & Norconk, M. A. (1993). Physical and chemical properties of fruit and seeds eaten by Pithecia and Chiropotes in Surinam and Venezuela. International Journal of Primatology, 14, 207–227.CrossRefGoogle Scholar
  24. Kool, K. (1993). The diet and feeding behavior of the silver leaf monkey (Trachypithecus auratus sondaicus) in Indonesia. International Journal of Primatology, 14, 667–700.CrossRefGoogle Scholar
  25. Lahm, S. A. (1986). Diet and habitat preferences of Mandrillus sphinx in Gabon: implications of foraging strategy. American Journal of Primatology, 11, 9–26.Google Scholar
  26. Leighton, M., & Leighton, D. R. (1982). The relationship of size of feeding aggregates to size of food patch: Howler monkeys (Alouatta palliata) feeding in Trichilia cipo fruit trees on Barro Colorado island. Biotropica, 14, 81–90.CrossRefGoogle Scholar
  27. Lopes, J. P., Albuquerque, H., Silva, Y., & Shrimpton, R. (1980). Aspectos nutritivos de algunos frutos da Amazonia. Acta Amazonica, 10, 755–758.Google Scholar
  28. Maisels, E., Gautier-Hion, A., & Gautier, J. P. (1994). Diets of two sympatric colobines in Zaire: More evidence on seed-eating in forests on poor soils. International Journal of Primatology, 15, 681–702.CrossRefGoogle Scholar
  29. Milton, K. (1981). Food choice and digestive strategies of two sympatric primate species. American Naturalist, 117, 496–505.CrossRefGoogle Scholar
  30. Mowry, C. B., Decker, B. S., & Shure, D. J. (1996). The role of phytochemistry in dietary choices of Tana River red colobus monkeys (Procolobus badius rufomitratus). International Journal of Primatology, 17, 63–84.CrossRefGoogle Scholar
  31. Norconk, M. A. (1996). Seasonal variation in the diets of white-faced and bearded sakis (Pithecia pithecia and Chiropotes satanas) in Guri Lake, Venezuela. In M. A. Norconk, A. L. Rosenberger, & P. A. Garber (Eds.), Adaptive radiations of Neotropical primates (pp. 403–548). New York: Plenum.CrossRefGoogle Scholar
  32. Norconk, M. A., & Conklin-Brittain, N. L. (2004). Variation on frugivory: The diet of Venezuelan white-faced sakis. International Journal of Primatology, 25, 1–26.CrossRefGoogle Scholar
  33. Norconk, M. A., Grafton, B. W., & Conklin-Brittain, N. L. (1998). Seed dispersal by Neotropical seed predators. American Journal of Primatology, 45, 103–126.PubMedCrossRefGoogle Scholar
  34. Peres, C. A. (1991). Seed predation of Cariniana micrantha (Lecythidaceae) by brown capuchin monkeys in Central Amazonia. Biotropica, 23, 262–270.CrossRefGoogle Scholar
  35. Peres, C. A. (1993). Notes on the ecology of buffy saki monkeys (Pithecia albicans, Gray 1860): A canopy seed-predator. American Journal of Primatology, 31, 129–140.CrossRefGoogle Scholar
  36. Peres, C. A. (1994). Diet and feeding ecology of gray woolly monkeys (Lagothrix lagotricha cana) in central Amazonia: Comparisons with other atelines. American Journal of Primatology, 15, 333–372.CrossRefGoogle Scholar
  37. Pitman, N., Vriesendorp, C., & Moskovits, D. (2003). Peru: Yavari. Rapid Biological Inventories Report 11. Chicago: The Field Museum.Google Scholar
  38. Rosenberger, A. L. (1992). Evolution of feeding niches in New World monkeys. American Journal of Physical Anthropology, 88, 525–562.PubMedCrossRefGoogle Scholar
  39. Rosenberger, A. L., Norconk, M. A., & Garber, P. A. (1996). New perspectives on the pitheciines. In M. A. Norconk, A. L. Rosenberger, & P. A. Garber (Eds.), Adaptive radiations of Neotropical primates (pp. 329–333). New York: Plenum.CrossRefGoogle Scholar
  40. Setz, E. (1994). Feeding ecology of golden-faced sakis. Neotropical Primates, 2, 13–14.Google Scholar
  41. Stevenson, P. R., Quiñones, M. J., & Ahumada, J. A. (2000). Influence of fruit availability on ecological overlap among four Neotropical primates at Tinigua National Park, Colombia. Biotropica, 32, 533–544.Google Scholar
  42. Stickel, L. F. (1954). A comparison of certain methods of measuring home range of small mammals. Journal of Mammology, 35, 1–15.CrossRefGoogle Scholar
  43. Sutherland, W. J. (2000). The conservation handbook: Techniques in research, management and policy. Oxford: Blackwell Science.Google Scholar
  44. Terborgh, J. (1983). Five New World primates: A study in comparative ecology. Princeton: Princeton University Press.Google Scholar
  45. Tutin, C. E. G., Ham, R. M., White, L. J. T., & Harrison, M. J. S. (1997). The primate community of the Lope Reserve, Gabon: Diets, responses to fruit scarcity, and effects on biomass. American Journal of Primatology, 42, 1–24.PubMedCrossRefGoogle Scholar
  46. Ungar, P. (1995). Fruit preferences of four sympatric primates at Ketambe, Northern Sumatra, Indonesia. International Journal of Primatology, 16, 221–246.CrossRefGoogle Scholar
  47. van Roosmalen, M. G. M., Mittermeier, R. A., & Fleagle, J. G. (1988). Diet of the northern bearded saki (Chiropotes santanas chiropotes): A Neotropical seed predator. American Journal of Primatology, 14, 11–35.CrossRefGoogle Scholar
  48. Waser, P. M. (1984). Ecological differences and behavioral contrasts between two mangabey species. In P. S. Rodman & J. G. H. Cant (Eds.), Adaptations for foraging in nonhuman primates (pp. 195–216). New York: Columbia University Press.Google Scholar
  49. Yamashita, N. (1996). Seasonal and site-specific patterns in mechanical dietary properties of Malagasy lemurs. American Journal of Physical Anthropology, 22, 249.Google Scholar

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© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  1. 1.Department of PsychologyUniversity of St. Andrews, St. Mary’s CollegeSt. AndrewsUK
  2. 2.Durrell Institute of Conservation and EcologyUniversity of KentCanterburyUK

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