Intercommunity interactions and killings in central chimpanzees (Pan troglodytes troglodytes) from Loango National Park, Gabon

Laura Martínez-Íñigo,Pauline Baas,Harmonie Klein,Tobias Deschner,Simone Pika

doi:10.1007/s10329-021-00921-x

Laura Martínez-Íñigo, Pauline Baas + Show 3 more

Open Access

https://doi.org/10.1007/s10329-021-00921-x

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Abstract

Intercommunity competition in chimpanzees (Pan troglodytes) has been widely studied in eastern (P. t. schweinfurthii) and western (P. t. verus) communities. Both subspecies show hostility towards neighboring communities but differ in rates of lethal attacks and female involvement. However, relatively little is known about the territorial behavior of the two other subspecies, central (P. t. troglodytes) and Nigeria-Cameroon chimpanzees (P. t. ellioti). Here, we present the first insights into intercommunity interactions of individuals of a community of central chimpanzees living in the Loango National Park in Gabon. The presence of individuals of neighboring communities in the Rekambo home range was assessed using 27 camera traps. Information was compiled on intergroup interactions recorded before (2005–2016) and after (January 2017–June 2019) the habituation of the community. Individuals from neighboring communities entered the core area, where nine out of 16 recorded intercommunity encounters occurred. Males were the main participants in territorial patrols and intercommunity aggressions. Females were part of all six territorial patrols recorded and dependent offspring participated in five patrols. Females were involved in intercommunity aggression in five out of twelve recorded encounters in which there was visual contact between communities. While the intercommunity encounter rate was lower than that reported across most other long-term chimpanzee sites, the annual intercommunity killing rate was among the highest. These results suggest that the frequency of lethal attacks at Loango is comparable to that reported for the eastern subspecies. In contrast, female involvement in intercommunity interactions mirrors that of the western subspecies.

Highlights

Social animals live in groups usually surrounded by other groups of conspecifics that compete against each other for limited resources (Tanner 2006; Cassidy et al 2017; Strong et al 2018)
We considered that a camera trap event showed a territorial patrol if it contained all these elements
From January 2017 to June 2019, parties of chimpanzees of the Rekambo community were followed for 831 days for a total of 8837 h

Summary

Introduction

Social animals live in groups usually surrounded by other groups of conspecifics that compete against each other for limited resources (Tanner 2006; Cassidy et al 2017; Strong et al 2018). Chimpanzees live in fission–fusion communities of up to 200 individuals with multiple adult females and males and their offspring, but spend most of their time in smaller parties of varying size and composition (e.g., Nishida 1979; Goodall 1986; Boesch and Boesch-Achermann 2000; Watts and Mitani 2015). Sometimes intruding deep (> 1 km; deep incursion) into the territory of other communities (Nishida et al 1985; Goodall 1986; Boesch and Boesch-Achermann 2000; Wilson et al 2004; Mitani and Watts 2005). Most intercommunity interactions consist of acoustic contacts at long distances (i.e., pant-hoots and drumming, Boesch and Boesch-Achermann 2000; Crofoot and Wrangham 2010) but can escalate into lethal attacks (e.g., Wilson et al 2014)

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