Ranging and territoriality in African Apes
- 1Harvard University
Abstract
Intergroup relations vary strikingly among African apes, with only chimpanzees showing intense, often lethal territoriality. The economic defendability hypothesis proposes that such territorial behaviour is favored where home ranges can be economically defended, as indexed by the ratio of daily travel distance to home range diameter. To test this idea, we compiled and analyzed comparable data on yearly home range size, daily travel distance and defendability indices from one population of each nonhuman African ape species and integrated these with comparable published data. We find that bonobos had substantially larger home ranges and longer daily travel distances than chimpanzees and gorillas, contradicting a prevailing assumption that bonobos experience higher or more reliable food abundance. Defendability indices were higher in chimpanzees and bonobos than in mountain gorillas, but did not differ significantly between chimpanzees, bonobos, and western gorillas. Overall, our results indicate that economic defendability alone cannot explain interspecific variation in territoriality and that our current understanding of ecological differences between the species of the genus Pan have to be revised. Possible additional factors shaping space use of neighboring groups include mate competition within groups.
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BibTeX
@misc{surbeck2026ranging,
title = {{Ranging and territoriality in African Apes}},
author = {M. Surbeck and R. Supple and A. P. Massaro and D. C. Mjungu and M. M. Robbins and M. L. Wilson},
howpublished = {bioRxiv},
year = {2026},
month = nov,
doi = {10.64898/2026.11.03.763879},
url = {https://www.biorxiv.org/content/10.64898/2026.11.03.763879v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Ranging and territoriality in African Apes
AU - M. Surbeck
AU - R. Supple
AU - A. P. Massaro
AU - D. C. Mjungu
AU - M. M. Robbins
AU - M. L. Wilson
PY - 2026
DA - 2026/11/03
PB - bioRxiv
DO - 10.64898/2026.11.03.763879
UR - https://www.biorxiv.org/content/10.64898/2026.11.03.763879v1
AB - Intergroup relations vary strikingly among African apes, with only chimpanzees showing intense, often lethal territoriality. The economic defendability hypothesis proposes that such territorial behaviour is favored where home ranges can be economically defended, as indexed by the ratio of daily travel distance to home range diameter. To test this idea, we compiled and analyzed comparable data on yearly home range size, daily travel distance and defendability indices from one population of each nonhuman African ape species and integrated these with comparable published data. We find that bonobos had substantially larger home ranges and longer daily travel distances than chimpanzees and gorillas, contradicting a prevailing assumption that bonobos experience higher or more reliable food abundance. Defendability indices were higher in chimpanzees and bonobos than in mountain gorillas, but did not differ significantly between chimpanzees, bonobos, and western gorillas. Overall, our results indicate that economic defendability alone cannot explain interspecific variation in territoriality and that our current understanding of ecological differences between the species of the genus Pan have to be revised. Possible additional factors shaping space use of neighboring groups include mate competition within groups.
ER -