fruit sharing for apparent social, not nutritional, purposes:

American Journal of Primatology
Volume 65, Issue 4 , Pages 385 - 391

Fruit sharing between wild adult chimpanzees (Pan troglodytes schweinfurthii):
a socially significant event?
Katie E. Slocombe, Nicholas E. Newton-Fisher

Abstract
Although food sharing is a habitual aspect of chimpanzee (Pan troglodytes)
life, sharing of plant foods between unrelated adults is rare. Observations of
such behavior have typically been interpreted as the outcome of a process by
which individuals that are otherwise unable to gain access to the food manage
to obtain a nutritional benefit. Here we present behavioral details and an
acoustic analysis regarding an observation of food sharing between unrelated
adult wild chimpanzees that we suggest cannot be explained using traditional
nutrition-based models. Instead we propose that the exchange is only
understandable as a socially important event, and we cite two further
observations in the same population that support this suggestion.

http://www3.interscience.wiley.com/cgi-bin/abstract/110471263/ABSTRACT

Tom Billings