Cultivated cocoa spread by wild chimpanzees, research finds

Thursday, 24 November 2016

Adult chimpanzee eating cacao fruit

A newly published study by researchers at Oxford Brookes University, the Centre for Research in Anthropology (Lisbon) and Kyoto University (Japan) has found that wild chimpanzees have been responsible for the dispersal of human-cultivated cocoa.

Researchers observed a group of chimpanzees at Bossou in the Republic of Guinea, West Africa over a three-year period and these latest findings evidence the complex behavioural and ecological connections between coexisting human and nonhuman great apes in forest-farm mosaic areas.

Dr Kimberley Hockings, Research Fellow at Oxford Brookes University and lead researcher of the study said: “Chimpanzees ingest the cacao pulp and either spit out the large seeds in unripe cacao fruit or swallow the seeds from ripe cacao fruit, which are consequently deposited in faeces.”

From ecological surveys carried out in 2011 and 2013, the research has shown that the chimpanzees distributed cacao extensively throughout their home range which is a mixture of forest and plantation areas. The further away from the cacao plantation the seeds were dispersed, the more likely the cacao plants were to survive. Cacao plants within the forest did not produce fruit due to the dense upper canopy restricting light.

This research has highlighted the possibility that the dispersal of crops by animals at other sites has the potential to positively impact the ability of wildlife to coexist in human-impacted habitats, especially if farmers gain economic benefits through the wildlife’s dispersal of crops.

Dr Kimberley Hockings, Research Fellow, Oxford Brookes University

When they deposited seeds in a plantation however, cacao plants produced fruits as a result of farmers’ identifying the cacao saplings that chimpanzees ‘planted’ and ensuing that weeds and over vegetation surrounding the saplings were cut.

Later, chimpanzees were observed feeding on cacao from the mature plants in the plantation that they had originally spread to that location.

The plantation owner described how he identified the cacao seedlings deposited by chimpanzees within his plantation and neighbouring forest that he subsequently cleared to expand his plantation.

Owing to the high economic value of cacao, the owner frequently cleared any vegetation and removed most large canopy trees to provide optimal growing requirements for the cacao.

As a result of these maintenance activities, he emphasised his ownership of the cacao, despite acknowledging the cacao had been ‘planted’ by the chimpanzees.

Dr Hockings continued: “This research has highlighted the possibility that the dispersal of crops by animals at other sites has the potential to positively impact the ability of wildlife to coexist in human-impacted habitats, especially if farmers gain economic benefits through the wildlife’s dispersal of crops. It’s also interesting from the perspective of chimpanzees creating their own niche.”

The study is part of an upcoming special issue in the International Journal of Primatology on primate behavioural flexibility in agricultural landscapes and the sustainability of human-primate interactions. The special issue will be guest co-edited by Dr Kimberley Hockings and Dr Matthew McLennan at Oxford Brookes University, and Noemi Spagnoletti at the University of Sao Paulo.

The full paper can be read online.

More information about Oxford Brookes’ research on primate conservation can be found on the Department of Social Sciences webpages.

Image: An adult male chimpanzee at Bossou feeding on ripe cacao fruit. Credit: Nicola Bryson-Morrison, University of Kent.