Reports

Program No.18-013

Fieldwork in  Tiete Ecological Park, Brazil.

TSUTSUMI SAYAKA

2nd August,2006 - 20th September,2006

I conducted field experiments on social intelligence involved in tool use by semi-wild capuchin monkeys in Tiete Ecological Park, Brazil. I first visited the University of Sao Paulo to discuss research plan with Dr. Ottoni who has done an extensive study on capuchin tool use in the park. I then conducted preliminary observation and collected basic data on social rank and tool use patterns for refining experimental conditions. Based on these basic data, I set up an experiment at one of the monkeys' most preferred sites of tool use in the park. The experiment consisted of several conditions where monkeys were able to use one or more sets of stone tools, either alone or with other monkeys. I recorded the monkey's choice of stone tools and saw if this was influenced by the number of monkeys at the site (i.e. alone or with other monkeys), the social rank of other monkeys, and the arrangement of stone tools. The results suggest that the monkeys' choice of stone tools was socially influenced, by the presence of other monkeys and by their social rank, when the physical factors of the tools were controlled. Further investigation on social value of stone tools is now in progress.

capuchin monkey using stone tool

Tiete Ecological Park

HOPE Project<>