Tool Use Observed in 2nd Group of Chimps
The noise came from the trees: crack, crack, crack.
As the researchers and their village guides crept closer, they saw something that was not supposed to be happening in the Ebo forest in the central African nation of Cameroon: chimpanzees using rocks as hammers to break open tough-shelled nuts.
Previous research had found that kind of tool use only in chimps 1,000 miles away, across the wide N’Zo-Sassandra River in Ivory Coast. Researchers thought the behavior was either a genetic trait or maybe a learned skill passed from one generation to another.
The discovery of tool use among chimps in Cameroon, separated from their cousins in Ivory Coast by the “information barrier” of the river, suggests that the skill was invented independently in each place, according to a study published Tuesday in the journal Current Biology.
Lead author Bethan J. Morgan, a postdoctoral researcher from the San Diego Zoo, and senior research assistant Ekwoge E. Abwe reported seeing three adult chimps breaking coula nuts with quartz stones. When the animals spotted the researchers, a female chimp and a chimp of undetermined gender fled, but a male stayed behind, continuing to break nuts for three minutes.
The ground beneath the coula tree was littered with broken nutshells and quartz stones.
Morgan said the discovery pointed out how little might be known about the chimp subspecies Pan troglodytes vellerosus even as it is in danger of extinction by “bushmeat” poachers.
She said she hoped the find would spark new interest in preservation among environmentalists and African nations. Although the chimp is on a protected list in Cameroon and neighboring Nigeria, poaching is rampant.
Interaction between researchers and hunters has not been pleasant. One group, Morgan said, threatened to burn down the researchers’ camp.
“Luckily, other field assistants were wonderful and stayed in the forest and protected the campsite,” she said from Cameroon in a telephone interview. “None of these forests are safe.”
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