Abstract # 2210 Poster # 143:

Scheduled for Friday, June 22, 2007 05:00 PM-07:00 PM: Session 14 (South Main Hall) Poster Presentation

Social Learning of Tool-use Skills in Captive Chimpanzees (pan troglodytes) and Gorillas (gorilla gorilla gorilla)

T. N. Melber1, E. V. Lonsdorf1,2 and S. R. Ross1
1Lincoln Park Zoo, Lester E. Fisher Center for the Study and Conservation of Apes, 2001 N. Clark St., Chicago, IL 60659, USA, 2University of Chicago Committee on Evolutionary Biology
     Wild studies of the social processes involved in tool-use learning have been limited by the lack of ability to control several variables, and in captive studies by tool-use opportunities that are often presented in non-naturalistic contexts. We attempted to address these limitations by providing naïve subjects with a naturalistic device (built to simulate a termite mound) in which 1) the task’s difficulty and tool availability was controllable; 2) levels of interaction with the device were measured before food was presented; and 3) animals were housed in their natural social setting to more closely replicate how learning would occur in the wild. Both gorillas and chimpanzees participated in the experiment to allow comparative analyses of social learning processes across both species. Here we present data on tool-use skill acquisition by one group of chimpanzees and two groups of gorillas. Within the first four weeks, 5 of 7 chimpanzees were observed to have successfully acquired foodstuff. None of the 9 animals in the first gorilla group succeeded in the first four weeks, while 2 of 5 in the second gorilla group were successful. Acquisition rates of the second group were likely influenced by the presence of one non-naïve adolescent female. These results demonstrate that a comparative approach is valuable to investigate species differences in socially-learned tasks.