International Journal of Primatology

, Volume 19, Issue 6, pp 929–948 | Cite as

Seasonality in the Ecology and Life Histories of Mountain Gorillas (Gorilla gorilla beringei)

  • David P. Watts

Abstract

The abundance of food, especially that of fruit and often that of young leaves, varies considerably over time for most primates. This variation can depend on or be independent of seasonality in rainfall. Mountain gorillas (Gorilla gorilla beringei) in the Virungas are exceptional: their habitat contains almost no edible fruit, and they mostly eat perennially available herbs and vines that are densely and evenly distributed in much of their habitat. Earlier studies documented little consistent temporal variation in mountain gorilla diets and habitat use, except for seasonal use of bamboo by some groups, and documented no birth seasonality. Long-term data (≤ 7 years) on 6 mountain gorilla groups confirm these results for habitat use, except that they show some seasonality in use of the upper altitudinal extremes of the gorillas' home ranges for unclear reasons. Relatively low and inconsistent variation in habitat quality over time should lower the costs of grouping for gorillas compared to other apes. Long-term data also confirm the absence of seasonality in births and conceptions. However, they show that mortality rates and risk of respiratory infections vary directly with rainfall. These relationships are probably causal and may be mediated through thermoregulatory stress.

gorillas seasonality diet habitat use mortality 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

REFERENCES

  1. Altmann, J. (1980). Baboon Mothers and Infants, Harvard University Press, Cambridge, MA.Google Scholar
  2. Altmann, J. (1983). Costs of reproduction in baboons. In Aspey, W. P., and Lustick, S. I. (eds.), Behavioral Energetics, Ohio State University Press, Columbus, pp. 67–88.Google Scholar
  3. Badrian, N., and Malenky, R.K. (1984). Feeding ecology of Pan paniscus in the Lomako Forest, Zaire. In Susman, R. L. (ed.), The Pygmy Chimpanzee: Evolutionary Morphology and Behavior, pp. 275–299.Google Scholar
  4. Bailey, R., Jenike, M., Ellison, P., Bentley, G., Harrigan, A., and Peacock, N. (1992). The ecology of birth seasonality among agriculturalists in central Africa. J. Biosoc. Sci. 24: 393–412.Google Scholar
  5. Brewis, A., Laycock, J., and Huntsman, J. (1996). Birth nonseasonality on the Pacific equator. Current Anthropol. 37: 842–851.Google Scholar
  6. Dunbar, R. I. M. (1980). Demographic and life history variations of a population of gelada baboons. J. Anim. Ecol. 49: 485–506.Google Scholar
  7. Foley, R. (1987). Another Unique Species, J. Wiley, New York.Google Scholar
  8. Fossey, D., and Harcourt, A. H. (1977). Feeding ecology of free ranging mountain gorilla (Gorilla gorilla beringei). In Clutton-Brock, T. H. (ed.), Primate Ecology, Academic Press, New York, pp. 415–447.Google Scholar
  9. Goodall, A. G. (1977). Feeding and ranging behavior of a mountain gorilla group (Gorilla gorilla beringei) in the Tshibinda-Kahuzi region (Zaire). In Clutton-Brock, T. H. (ed.), Primate Ecology, Academic Press, New York, pp. 449–479.Google Scholar
  10. Goodall, J. (1983). Population dynamics during a 15-year period in one community of free-living chimpanzees in the Gombe National Park, Tanzania. Z. Tierpsychol. 61: 1–60.Google Scholar
  11. Goodall, J. (1986). The Chimpanzees of Gombe, Harvard University Press, Cambridge, MA.Google Scholar
  12. Hastings, B. E. (1991). The veterinary management of a laryngeal airsac infection in a free-ranging mountain gorilla. J. Med. Primatol. 7: 361–364.Google Scholar
  13. Hill, K., and Hurtado, A.M. (1996). Ache Life History, Aldine de Gruyter, New York.Google Scholar
  14. Hill, K., Hawkes, K., Hurtado, A. M., and Kaplan, H. (1984). Seasonal variance in the diet of Ache hunter-gatherers in Paraguay. Hum. Ecol. 12: 145–180.Google Scholar
  15. Kenny, D. (1988). Respiratory outbreak in the Virungas mountain gorillas. Unpublished report to the Morris Animal Foundation.Google Scholar
  16. Kiltie, R. (1988). Gestation as a constraint on the evolution of seasonal breeding in mammals. In Boyce, M. S. (eds.), Evolution of Life Histories of Mammals, Yale University Press, New Haven, CT, pp. 257–289.Google Scholar
  17. Kuroda, S., Nishihara, T., Suzuki, S., and Oko, R. A. (1996). Sympatric chimpanzees and gorillas in the Ndoki Forest, Congo. In McGrew, W.C., Marchant, L.F., and Nishida, T. (eds.), Great Ape Societies, Cambridge University Press, Cambridge, pp. 71–81.Google Scholar
  18. Lee, R.B. (1983). The !Kung San: Men, Women, and Work in a Foraging Society, Cambridge University Press, Cambridge.Google Scholar
  19. MacNeilage, A. J. (1995). Mountain Gorillas in the Virunga Volcanoes: Ecology and Carrying Capacity, Unpublished Ph.D. thesis, University of Bristol, Bristol.Google Scholar
  20. Mwanza, N. J., Yamagiwa, J., Yumoto, T., and Maruhashi, T. (1992). Distribution and range utilization of eastern lowland gorillas. In Itoigawa, N., Sugiyama, Y., Sackett, G.P., and Thompson, R. K. R. (eds.), Topics in Primatology, Vol. 2: Behavior, Ecology, and Conservation, University of Tokyo Press, Tokyo, pp. 283–300.Google Scholar
  21. Nishida, T., Takasaki, H., and Takahata, Y. (1990). Demography and reproductive profiles. In Nishida, T. (ed.), The Chimpanzees of the Mahale Mountains, University of Tokyo Press, Tokyo, pp. 63–98.Google Scholar
  22. Ohsawa, H., and Dunbar, R. I. M. (1984). Variation in the demographic structure and dynamics of gelada baboon populations. Behav. Ecol. Sociobiol. 15: 231–240.Google Scholar
  23. Plumptre, A. J. (1994). The effects of trampling damage on the vegetation of the Parc National des Volcans, Rwanda. Afr. J. Ecol. 32: 115–129.Google Scholar
  24. Plumptre, A.J. (1995). The chemical composition of montane plants and its influence on the diet of the large mammalian herbivores in the Parc National des Volcans, Rwanda. J. Zool. (London) 235: 323–338.Google Scholar
  25. Plumptre, A. J., and Harris, S. (1995). Estimating biomass of large mammalian herbivores in a tropical montane forest: A method of faecal counting that avoids assuming a “steady state” system. J. Appl. Ecol. 32: 111–120.Google Scholar
  26. Remis, M. (1994). Feeding Ecology and Positional Behavior of Lowland Gorillas. Unpublished Ph.D. thesis, Department of Anthropology, Yale University, New Haven, CT.Google Scholar
  27. Rogers, M. E., Williamson, E. A., Tutin, C. E. G., and Fernandez, M. (1988). Effects of the dry season on gorilla diet in Gabon. Primate Rep. 22: 25–33.Google Scholar
  28. Rogers, M. E., Maisels, F., Williamson, E. A., Fernandez, M., and Tutin, C. E. G. (1990). Gorilla diet in the Lope Researve, Gabon: A nutritional analysis. Oecologia 84: 326–339.Google Scholar
  29. Sabater Pi, J. (1977). Contribution to the study of alimentation of lowland gorillas in the natural state, Rio Muni, Republic of Equatorial Guinea (West Africa). Primates 18: 183–204.Google Scholar
  30. Schaller, G. (1963). The Mountain Gorilla, University of Chicago Press, Chicago.Google Scholar
  31. Struhsaker, T. T. (1997). Ecology of an African Rainforest, University Presses of Florida, Gainesville.Google Scholar
  32. te Boekhoerst, I. J. A., Schurmann, V. L., and Sugardjito, J. (1990). Residential status and seasonal movement of wild orangutans in the Gunung Leuser Reserve (Sumatra, Indonesia). Anim. Behav. 39: 1098–1109.Google Scholar
  33. Trivers, R.L. (1974). Parent-offspring conflict. Am. Zool. 11: 249–264.Google Scholar
  34. Vedder, A.L. (1984). Movement patterns of a group of free-ranging mountain gorillas (Gorilla gorilla beringei) and their relationship to food availability. Am. J. Primatol. 7: 73–88.Google Scholar
  35. Wallis, J. (1995). Seasonal influences on reproduction in chimpanzees of Gombe National Park. Int. J. Primatol. 16: 435–452.Google Scholar
  36. Waterman, P., Choo, G., Vedder, A. L., and Watts, D. P. (1983). Digestibility, digestion inhibitors, and nutrients from herbaceous foliage from an Afromontane flora and its comparison with other tropical flora. Oecologia (Berlin) 60: 244–249.Google Scholar
  37. Watts, D. P. (1983). Foraging Strategy and Socioecology of Mountain Gorillas (Pan gorilla beringei), Unpublished Ph.D. thesis, Department of Anthropology, University of Chicago, Chicago.Google Scholar
  38. Watts, D. P. (1984). Composition and variability of mountain gorilla diets in the central Virungas. Am. J. Primatol. 7: 323–356.Google Scholar
  39. Watts, D. P. (1987). Effects of mountain gorilla foraging activities on the productivity of their food plant species. Afr. J. Ecol. 25: 155–163.Google Scholar
  40. Watts, D. P. (1988). Environmental influences on mountain gorilla time budgets. Am. J. Primatol. 15: 295–312.Google Scholar
  41. Watts, D. P. (1989). Infanticide in mountain gorillas: New cases and a reconsideration of the evidence. Ethology 81: 1–18.Google Scholar
  42. Watts, D. P. (1991a). Strategies of habitat use by mountain gorillas. Folia Primatol. 56: 1–16.Google Scholar
  43. Watts, D. P. (1991b). Mountain gorilla reproduction and sexual behavior. Am. J. Primatol. 24: 211–226.Google Scholar
  44. Watts, D. P. (1994). The influence of male mating tactics on habitat use in moutain gorillas. Primates 35: 35–47.Google Scholar
  45. Watts, D. P. (1996). Comparative socioecology of gorillas. In McGrew, W. C., Marchant, L. F., and Nishida, T. (eds.), Great Ape Societies, Cambridge University Press, Cambridge, pp. 16–28.Google Scholar
  46. Watts, D. P. (1998a). Long-term habitat use by moutain gorillas (Gorilla gorilla beringei). 1. Consistency, variation, and home range size and stability. Int. J. Primatol. 19: 651–680.Google Scholar
  47. Watts, D. P. (1998b). Long-term habitat use by mountain gorillas (Gorilla gorilla beringei). 2. Reuse of foraging areas in relation to resource abundance, quality, and depletion. Intl. J. Primatol. 19: 681–702.Google Scholar
  48. Watts, D. P., and Pusey, A. E. (1993). Behavior of juvenile and adolescent great apes. In Pereira, M. E., and Fairbanks, L. (eds.), Behavior of Juvenile and Adolescent Great Apes, Cambridge University Press, Cambridge, pp. 148–171.Google Scholar
  49. Weber, A. W., and Vedder, A. L. (1983). Population dynamics of the Virunga gorillas: 1959–1978. Biol. Conserv. 26: 341–366.Google Scholar
  50. Williamson, E. A., Tutin, C. E. G., Rogers, M. E., and Fernandez, M. (1990). Composition of the diet of lowland gorillas at Lope in Gabon. Am. J. Primatol. 21: 265–277.Google Scholar
  51. Withers, J. (1992). Comparative Animal Physiology, Saunders/Harcourt Brace Jovanovich, New York.Google Scholar
  52. Wrangham, R. W. (1977). Feeding behavior of chimpanzees in Gombe National Park, Tanzania. In Clutton-Brock, T. H. (ed.), Primate Ecology, Academic Press, New York, pp. 504–538.Google Scholar
  53. Wrangham, R. W. (1979). On the evolution of ape social systems. Soc. Sci. Inform. 18: 335–368.Google Scholar
  54. Wrangham, R. W., Conklin, N. L., Chapman, C. A., and Hunt, K. D. (1992). The significance of fibrous foods for Kibale Forest chimpanzees. In Whiten, A., and Widdowson, E. M. (eds.), Foraging Strategies and Natural Diets of Monkeys, Apes, and Humans, Clarendon Press, Oxford, pp. 11–18.Google Scholar
  55. Wrangham, R. W., Chapman, C. A., Clark Arcadi, A. P., and Isibirye-Basuta, G. (1996). Social ecology of Kanyawara chimpanzees: implications for understanding the costs of great ape groups. In McGrew, W. C., Marchant, L. F., and Nishida, T. (eds.), Great Ape Societies, Cambridge University Press, Cambridge, pp. 45–57.Google Scholar
  56. Yamagiwa, J., and Mwanza, M. (1994). Day-journey length and daily diet of solitary male gorillas in lowland and highland habitats. Int. J. Primatol. 15: 207–224.Google Scholar
  57. Yamagiwa, J., Mwanza, M., Yumoto, T., and Maruhashi, T. (1994). Seasonal change in the composition of the diet of eastern lowland gorillas. Primates 35: 1–14.Google Scholar

Copyright information

© Plenum Publishing Corporation 1998

Authors and Affiliations

  • David P. Watts
    • 1
  1. 1.Department of AnthropologyYale UniversityNew Haven

Personalised recommendations