In a novel example of vocal learning, chimpanzees picked up what might be considered the equivalent of a Scottish brogue after they were moved from a Dutch zoo to Edinburgh.
“It’s the first time we’ve seen another primate species — not humans — change the structure of the call that they gave for a specific object by socially learning it,” University of York psychologist Katie Slocombe told NBC News. Slocombe and her colleagues reported the phenomenon Thursday in the journal Current Biology.
The specific object in this case is an apple, one of the chimps’ favorite foods. They typically give out a series of grunts when they see apples, or are eating apples. But chimps from the Beekse Bergen Safari Park in the Netherlands use high-pitched grunts, while chimps from the Edinburgh Zoo in Scotland use a lower pitch.
In 2010, nine chimps from the Dutch zoo were due to be moved to the Scottish zoo for breeding purposes, and that provided a golden opportunity to find out whether chimps, like humans, learn a new lingo when they fall in with a new social group.
The researchers recorded the calls made by the Dutch chimps as well as the Scottish chimps before the move. They followed up with a new set of recordings during the chimps’ getting-to-know-you phase in 2011, and after the two groups were fully blended together in 2013. Slocombe and her colleagues found that the Dutch visitors changed their call for apples to conform with the pitch pattern used by their Scottish hosts.
Social connections play a part
The key to the switchover wasn’t simply being exposed to the different call in a new environment. Instead, the researchers said the change took hold only after “strong social relationships had formed” between the two groups.
So why did the Dutch chimps change to accommodate the Scottish chimps, rather than vice versa? Were the Dutch chimps merely following the lead of the combined groups’ dominant male, an Edinburgher? The researchers say previous studies of wild vervet monkeys point to a different reason.
“An alternative is that conformity mechanisms may have motivated the immigrants to adopt the vocal norms of the host group,” they wrote.
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SOURCE: NBC News, Alan Boyle