The local customs that define human cultures in important ways also
exist in the ape world, suggests a study reported online June 7th in
Current Biology, a Cell Press publication. Indeed, captive chimpanzees,
like people, can readily acquire new traditions, and those newly
instituted "cultural practices" can spread to other troops.
have robust evidence that in chimpanzees there is a considerable
capacity for cultural spread of innovations," said Dr. Andrew Whiten of
the University of St. Andrews in Scotland. "This strengthens the
interpretation of cases of behavioral diversity in the wild as socially
transmitted traditions. Moreover, we have now shown that chimpanzees
can sustain cultures that are made up of several traditions. This again
is consistent with what is seen in the wild, where chimpanzees are
thought to show up to 20 traditions that define their unique local
Documented examples of behavioral differences among chimpanzees in
nature include various types of tool use, including hammers and
pestles; social behaviors like overhead hand-clasping during mutual
grooming; courtship rituals like leaf-clipping, in which leaves are
noisily clipped with the teeth; and methods for eradicating parasites
by either stabbing or squashing them. However, the idea that such
behaviors constitute traditions passed on through observational
learning "relies heavily on circumstantial evidence that alternative
genetic or environmental explanations are implausible."
Whiten's international team, including colleagues in Scotland and
others from Emory University's Yerkes National Primate Research Center
and the University of Texas, has tackled the question experimentally by
"seeding" novel forms of tool use and food extraction in different
captive chimpanzee communities.
Over time, the researchers saw
ten of these new behaviors spread and become full-fledged, local
traditions. As a result, the communities at Yerkes and the University
of Texas now display their own unique cultures.
University of Texas, where several groups are next-door neighbors
within eyeshot of each other, four of the new traditions proved
catching. The learned foraging practices spread from one group to
another, and then on to a third.
The findings have important implications for understanding the ability of primates to adapt over time.
learning is important for evolutionary adaptation because it can be so
much faster than that which occurs through genetic change; and, unlike
learning by one's own efforts-for example, by trial and error-it can be
very efficient because one is standing on the shoulders of what
previous generations achieved," Whiten said.
Cell Press. June 2007.