May 8, 2009
Gorillas Use Hand-Clapping To Communicate With Family
Researchers in the forests of central Africa have observed methods used by mother gorillas to keep their families in line.
The report, published in the journal Primates, marks only the second time such activity has been seen among wild western lowland gorillas.
While monitoring at the Lac Tele Community Reserve Project in the Republic of Congo, Ammie Kalan of Oxford Brookes University, in Oxford, UK and Hugo Rainey of the Wildlife Conservation Society, noted that they clapped their hands in order to communicate with family members.
"What struck me most was how it was conducted in such a controlled and deliberate manner while in a bipedal position; much like a human would hand clap," Ammie Kalan of Oxford Brookes University, in Oxford, UK, told BBC's Earth News.
"A female was able to exert control over her infant's behavior by hand-clapping. Which did remind me of a human mother."
Over a quarter of a century ago, Diane Fossey became the first researcher to observe such activity among primate families. She noted hand-clapping being used by a single wild mountain gorilla. She also reported that the female lost the behavior again within four years.
Primatologist J Michael Fay reported western lowland gorillas in the Central African Republic using hand-clapping 20 years ago, which he attributed to a response to human presence.
Kalan and Rainey documented the use of hand-clapping among four different groups of western lowland gorilla in the Likouala swamp within the Lac Tele Community Reserve.
Their observations included the use of hand-clapping among five adult female gorilla, four of whom had infants present.
On two separate occasions, they noted females clapped their hand to communicate with a male silverback in order to tell them that a human was present.
On one occasion, the silverback responded to the clapping by attempting to intimidate the human observers. On the other occasion, the silverback let out a loud road and beat his chest.
In yet another event, the onlookers startled three females in a tree who rapidly responded by clapping their hands five times in succession.
"We believe they were attempting to contact the silverback even after we were no longer posing a threat," Kalan said.
"It's a form of gestural communication that has largely been overlooked by gorilla researchers," says Kalan.
"It's used as a form of long distance communication with the silverback, even when humans are not posing an immediate threat, as well as to get the attention of group members. The hand clap allows the gorillas to maintain group cohesiveness."
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