SCIENCE

Wild Gorillas Seen Using Tools

Biologists have for the first time observed gorillas using tools in the wild: two females that independently used branches to check the depth of a pool or cross a muddy patch of ground in Africa's Congo Republic.

"This is a truly astounding discovery," said Thomas Breuer of the Wildlife Conservation Society at the Bronx Zoo in New York, who led the team that made the observations. "Tool usage in wild apes provides us with valuable insights into the evolution of our own species and the abilities of other species."

Previously, scientists had documented tool use in the wild among chimpanzees and orangutans and gorillas in zoos, but never before in wild gorillas.

The researchers first observed a female gorilla named Leah in a marshy clearing in the Congo Republic's Nouabale-Ndoki National Park attempting to wade through a pool on Oct. 9, 2004. When she got about waist-deep, Leah climbed out of the water, yanked a branch off a nearby tree and used it to test the pool's depth as she ventured farther in, the researchers reported.

Then on Nov. 21, a female named Efi used the trunk of a dead shrub to support herself with one hand while digging for herbs with the other, and also as a makeshift bridge over a muddy patch of ground.

"Although there are reports of tool use by captive gorillas, including object throwing and use of tools in feeding, there has been to our knowledge no reported case of tool use by wild gorillas, despite decades of field research," the researchers wrote in a paper published online last week in the journal PLoS Biology.

"The observed tool use involved gorillas from two different groups and thus could indicate independent inventions, perhaps reflecting past negative experiences with deep water," the researchers wrote.

-- Rob Stein

A Quake on Mars?

Scientists using NASA's venerable Mars Global Surveyor satellite to monitor the Martian surface have found new evidence that the planet may still be geologically active enough to have had a "marsquake" in 2003 or 2004.

By examining Surveyor photographs of a Martian crater, researchers confirmed that a dozen boulders perched on the crater lip in November 2003 had bounced down to the bottom by December 2004.