Merging groups of chimps adopt vocal accents to fit norm

EDINBURGH, Scotland, Feb. 6 (UPI) -- Foreign communities of chimps don't normally join forces in the wild -- they're too territorial. But when a group of chimpanzees from Sweden were moved to Scotland to join six local chimps at the Edinburgh Zoo, researchers took the opportunity to study the subtleties of animal integration.

One of the more interesting observations involved a simple round piece of fruit -- an apple. Not all chimps like apples, and thus, different populations respond to different foods differently. The Swedish chimps like apples very much, and generally respond to their presence with a high-pitched sound of delight. Scottish chimps are less enthusiastic, and remark so with a lower-pitched grunt of disappointment.

After a year of familiarizing themselves with their new surroundings and chimp neighbors, researchers found that the Swedes had lowered the tone and pitch of their apple-specific grunt to match the vocalization of their hosts. But while the newcomers were found to augment their voice, preference tests proved their love of apples didn't waver.

"As far as we know, this is the first evidence we've seen of a referential call being modified," study author Simon Townsend, an animal communications researcher at the University of Zurich, told The Verge.

"Our study shows that chimpanzee referential food calls are not fixed in their structure and that, when exposed to a new social group, chimpanzees can change their calls to sound more like their group mates," Katie Slocombe, a researcher at the University of York, said in a press release.

The study was published in the journal Current Biology.