Variation in hunting behaviour in neighbouring chimpanzee communities in the Budongo forest, Uganda.

Catherine Hobaiter,Caroline Mullins,Walter John Akankwasa,Klaus Zuberbühler,Liran Samuni

doi:10.1371/journal.pone.0178065

Abstract

Hunting and sharing of meat is seen across all chimpanzee sites, with variation in prey preferences, hunting techniques, frequencies, and success rates. Here, we compared hunting and meat-eating behaviour in two adjacent chimpanzee communities (Pan troglodytes schweinfurthii) of Budongo Forest, Uganda: the Waibira and Sonso communities. We observed consistent between-group differences in prey-species preferences and in post-hunting behaviour. Sonso chimpanzees show a strong prey preference for Guereza colobus monkeys (Colobus guereza occidentalis; 74.9% hunts), and hunt regularly (1–2 times a month) but with large year-to-year and month-to-month variation. Waibira chimpanzee prey preferences are distributed across primate and duiker species, and resemble those described in an early study of Sonso hunting. Waibira chimpanzees (which include ex-Sonso immigrants) have been observed to feed on red duiker (Cephalophus natalensis; 25%, 9/36 hunts), a species Sonso has never been recorded to feed on (18 years data, 27 years observations), despite no apparent differences in prey distribution; and show less rank-related harassment of meat possessors. We discuss the two most likely and probably interrelated explanations for the observed intergroup variation in chimpanzee hunting behaviour, that is, long-term disruption of complex group-level behaviour due to human presence and possible socially transmitted differences in prey preferences.

Highlights

Hunting and meat sharing is regularly observed in wild chimpanzees at all long-term studysites [1,2,3,4,5,6,7,8]
The availability of data from the Waibira chimpanzee community is limited by their recent habituation, we find a current difference in the hunting behaviour of two neighbouring chimpanzee communities in Budongo Forest, Uganda
Sonso chimpanzees show a clear preference for Guereza colobus monkeys, both in terms of their hunting activity and subsequent meat-eating behaviour

Summary

Introduction

Hunting and meat sharing is regularly observed in wild chimpanzees at all long-term studysites [1,2,3,4,5,6,7,8]. We present the first observations of hunting and meat-eating behaviour in a newly habituated group, the Waibira community of Budongo Forest, Uganda, and compare them with long-term data of the neighbouring Sonso community. Both groups share the same forest environment and there is regular genetic flow between the groups. We are able to compare and contrast the behaviour of the two communities at a similar stage in habituation to human research presence using long-term records for the Sonso community and comparing with published records from Sonso and other communities Where all of these factors can be excluded, any remaining group-level behavioural differences become a candidate for a socially acquired ‘cultural’ variant. Fast-paced hunts are often high in the canopy and can be difficult to observe, even among well-habituated chimpanzees; prey species and subsequent meat-eating behaviour can be recorded accurately and reliably after the kill, and are the focus of this study

Method

Findings

Discussion