Abstract # 113:

Scheduled for Friday, June 20, 2008 05:00 PM-07:00 PM: Session 12 (Ball Rooms A and B) Poster Presentation

The development of termite-fishing skills in captive Western lowland gorilla infants (Gorilla gorilla gorilla)

S. A. Linick, E. V. Lonsdorf, S. R. Ross and M. S. Milstein
Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, 2001 North Clark Street, Chicago, IL 60614, USA
     Chimpanzees are well-known tool-users both in the wild and in captivity, but relatively little research has been conducted on tool-use in gorillas. Learning of termite-fishing by young chimpanzees has been described in detail, with evidence that these skills are transmitted from adults (usually mothers) to youngsters via a combination of individual and social learning mechanisms. We provided two groups of gorillas access to an artificial termite mound and recorded the behavioral activities of three gorilla infants at the mound (Male A=13 months, Male B=14 months, Female A=6 months) over three months, equally approximately 650 hours of observation per group. Results for all three infants show the majority of their time at the mound was spent only with their mothers and the dominant behavior recorded was “inactive”. However after one month, mound-related behaviors such as “poke” and “investigate” increased. There were significant inter-individual differences: Male A had significantly higher amounts of “poke” than Male B [t(1)=1.94, p=0.01] and Female A [t(1)=3.17, p<0.001]. Female A had higher amounts of “investigate” than both Male A and Male B, but the difference was not statistically significant. These early descriptions confirm that like chimpanzee infants, gorilla infants show growing interest in the termite mound by means such as poking and smelling, but that the first tangible signs of social learning of tool-use skills do not occur until a later age