Gorillas more than just ‘the big brutes in the forest’

FOR the first time, biologists have documented gorillas in the wild using simple tools, such as poking a stick in a swampy pool of water to check its depth.

Until now, scientists had seen gorillas use tools only in captivity. Tool use in the wild was thought to be a survival skill reserved for smaller chimpanzees and orangutans.

The research in the Republic of Congo was led by Thomas Breuer of the Wildlife Conservation Society at the Bronx Zoo in New York.

“This is a truly astounding discovery,” he said. “Tool usage in wild apes provides us with valuable insights into the evolution of our own species and the abilities of other species.”

Other scientists said the observations were important, but not surprising.

Mr Breuer’s observations were made in a marshy clearing in Nouabale-Ndoki National Park where monitoring has been ongoing since February 1995.

The first instance occurred when a female gorilla (nicknamed Leah) attempted to wade through a pool of water created by elephants, but found herself waist deep after only a few steps. Climbing out of the pool, she retrieved a branch and used the stick to test the depth of the water.

A second female gorilla (named Efi) used a detached tree trunk to support herself with one hand while digging for herbs with the other. She also used the trunk as a bridge to cross muddy ground.

Details of the findings are being published in the online journal PLoS (Public Library of Science) Biology.

Fairly or not, gorillas have been considered less capable than other great apes, in part because they have not been as extensively studied.

Chimps, for example, have been continuously observed in the field for 40 years. They have become stars of television documentaries and glossy magazine articles, displaying their extensive of use of rocks to break open hard-shelled nuts and sticks to ‘fish’ termites from mounds.

In contrast, gorillas are larger, stronger and slower.

Richard Carroll, a primate expert, said: “Chimps are portrayed as the super-ape and gorillas are the big brutes in the forest.

“Gorillas are very intelligent, but they don’t have to be as delicate as chimps - they can just smash open the termite nest.”

A decade ago, Mr Carroll reported seeing gorillas using sticks to ward off attacking leopards.

Mr Carroll said the new study was made possible by the establishment of protected parks in Congo.

The populations of gorillas and other great apes are severely imperilled by logging, hunting and outbreaks of the Ebola virus. And, civil war in Congo has made field science dangerous for years.