Abstract
The ranging patterns of western gorillas have been described in relation to their more frugivorous diet as compared to mountain gorillas. However, the lack of data from habituated groups prevents a full understanding of their ranging behavior and its implications for western gorilla social behavior. Unhabituated gorillas often flee from approaching researchers, possibly resulting in longer daily ranges and home range expansions and/or shifts. I report on the influence of habituation on the ranging patterns of a western gorilla group. I analyzed progress in habituation through changes in gorilla reactions, displayed upon detecting the observers. I measured daily path length and home range while following the group's trails and monitored diet via fecal analyses and direct observations. During the study period, habituation progressed and the gorillas increasingly ignored the arrival of observers. As a result, daily path lengths were longer during the early stages of habituation, when the gorillas were avoiding observers. There was no range expansion or shift, though the measure is more difficult to investigate, being subject to error due to variation in sample size. We recorded seasonal changes in the consumption of fruit by gorillas, but no direct effect on ranging patterns is detectable with the data available, which is likely a consequence of the combined effect of habituation and seasonality on group movements. The findings are not only important for understanding the extent of human influence while conducting research on wild gorillas but also suggest the need for caution when interpreting results from non-habituated gorillas.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bermejo, M. (1997). Study of western lowland gorillas in the Lossi Forest of North Congo and a pilot gorilla tourism plan. Gor. Cons. News 11: 6-7.
Blom, A., Cipolletta, C., Brunsting, A., and Prins, H. (2001). Ecological and Economic Impacts of Gorilla-Based Tourism in Dzanga-Sangha, Central African Republic, PhD Thesis, Wagenigen University, The Netherlands, pp. 91-124.
Calvert, J. J. (1985). Food selection by western gorillas (G. g. gorilla) in relation to food chemistry. Oecologia 65: 236-246.
Carroll, R. W. (1997). Feeding Ecology of Lowland Gorillas in the Dzanga-Sangha Dense Forest Reserve of the Central African Republic, PhD Thesis, Yale University, New Haven, CT.
Clutton-Brock, T. H., and Harvey, P. H. (1977). Species differences in feeding and ranging behaviour in primates. In Clutton-Brock, T. H. (ed.), Primate Ecology: Studies of Feeding and Ranging Behaviour in Lemurs, Monkeys, and Apes, Academic Press, London, pp. 557-584.
Doran, D. M., and McNeilage, A. (1998). Gorilla ecology and behavior. Evol. Anthropol. 6: 120-131.
Fay, J. M. (1997). The Ecology, Social Organization, Populations, Habitat and History of the Western Lowland Gorilla (Gorilla gorilla gorilla Savage and Wyman, 1847), PhD Thesis, Washington University, MS.
Goldsmith, M. (1996). Ecological Influences on the Ranging and Grouping Behavior of Western Lowland Gorillas at Bai Hokou, Central African Republic, PhD Thesis, State University of New York, Stony Brook, New York.
Goldsmith, M. (1999). Ecological constraints on the foraging effort of western lowland gorillas (Gorilla gorilla gorilla) at Bai Hokou, Central African Republic. Int. J. Primatol. 20: 1-23.
Harcourt, A. H. (1996). Is the gorilla a threatened species: How should we judge? Biol. Conserv. 75: 165-176.
Jones, C., and Sabater Pì, J. (1971). Comparative ecology of Gorilla gorilla (Savage and Whyman) and Pan troglodytes (Bluenbach) in Rio Muni, West Africa. Bibliogr. Primatol. 13: 1-96.
Kuroda, S. (1996). Sympatric chimpanzees and gorillas in the Ndoki Forest, Congo. In McGrew, W., Marchant, L., Nishida, T. (Eds.), Great Ape Societies, Cambridge University Press, Cambridge, UK, pp. 71-81.
Nishihara, T. (1995). Feeding ecology of western lowland gorillas in the Nouabale-Ndoki national park, Congo. Primates 36: 151-168.
Remis, M. (1994). Feeding Ecology and Positional Behavior of Western Lowland Gorillas (Gorilla gorilla gorilla) in the Central African Republic, PhD Thesis, Yale University, New haven, CT.
Remis, M. J. (1997a). Ranging and grouping patterns of western lowland gorilla group at Bai Hokou, Central African Republic. Am. J. Primatol. 43: 111-133.
Remis, M. J. (1997b). Western lowland gorillas (Gorilla gorilla gorilla) as seasonal frugivores: Use of variable resources. Am. J. Primatol. 4: 87-109.
Rogers, M. E., Maislels, F., Williamson, E. A., Fernandez, M., and Tutin, C. E. G. (1990). Gorilla diet in the Lopé Reserve, Gabon. Oecologia 84: 326-339.
Rogers, M. E., Williamson, E. A., Tutin, C. E. G., and Fernandez, M. (1988). Effects of dry season on gorilla diet in Gabon. Primate Rep. 22: 25-33.
Sabater Pì, 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.
Schaller, G. (1963). The Mountain Gorilla: Ecology and Behavior, University of Chicago Press, Chicago.
Tutin, C. E. G. (1996). Ranging and social structure of lowland gorillas in the Lopé Reserve, Gabon. In McGrew, W., Marchant, L., and Nishida, T. (Eds.), Great Ape Societies, Cambridge University Press, Cambridge, UK, pp. 58-70.
Tutin, C. E. G., and Fernandez, M. (1991). Responses of wild chimpanzees and gorillas to the arrival of primatologists: Behaviour observed during habituation. In Box, H. O. (ed.), Primate Responses to Environmental Change, Chapman and Hall, London, pp. 187-196.
Tutin, C. E. G., and Fernandez, M. (1993). Fecal analysis as a methods of describing diets of apes: Examples from sympatric gorillas and chimpanzees at Lopé, Gabon. Tropics 2: 189-197.
Tutin, C. E. G., Fernandez, M., Rogers, M. E., and Williamson, E. A. (1992). A preliminary analysis of the social structure of lowland gorillas in the Lopé Reserve, Gabon. In Itoigawa, N., Sugiyama, Y., Sackett, G. P., and Thompson, R. K. R. (Eds.), Topics in Primatology, Vol. 2, Behavior, Ecology and Conservation, Tokyo University Press, Tokyo, pp. 245-254.
Vedder, A. L. (1984). Movement patterns of a group of free-ranging mountain gorillas (Gorilla gorilla beringei) and their relation to food availability. Am. J. Primatol. 7: 73-88.
Watts, D. P. (1984). Composition and variability of mountain gorillas diet in the central Virungas. Am. J. Primatol. 7: 323-356.
Watts, D. P. (1991). Strategies of habitat use in mountain gorillas. Folia Primatolol. 56: 1-16.
Watts, D. P. (1998). Long term habitat use by mountain gorillas (Gorilla gorilla beringei). 1. Consistency, variation, and home range size and stability. Int. J. Primatol. 19: 651-679.
Watts, D. P. (2000). Mountain gorilla habitat use strategies and group movements. In Boinski, S., and Garber, P. (Eds.), On the Move, University of Chicago Press, Chicago, pp. 351-374.
White, L. J. T., Rogers, M. E., Tutin, C. E. G., Williamson, E. A., and Fernandez, M. (1995). Herbaceous vegetation in different forest types in the Lopé reserve, Gabon: Implications for keystone food availability. Afr. J. Ecol. 33: 124-141.
Williamson, E. A., Tutin, C. E. G., Rogers, M. E., and Fernandez, M. E. (1990). Composition of the diet of lowland gorillas at Lopé, Gabon. Am. J. Primatol. 21: 265-277.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Cipolletta, C. Ranging Patterns of a Western Gorilla Group During Habituation to Humans in the Dzanga-Ndoki National Park, Central African Republic. International Journal of Primatology 24, 1207–1226 (2003). https://doi.org/10.1023/B:IJOP.0000005988.52177.45
Issue Date:
DOI: https://doi.org/10.1023/B:IJOP.0000005988.52177.45