It was once thought only humans gestured to direct another person's attention, but such "referential" gesturing has now been observed in wild chimpanzees.
John Mitani, a University of Michigan anthropology professor, and colleague Simone Pika, a postdoctoral fellow in psychology at the University of St. Andrews in Scotland, observed male chimps habitually using "directed scratches" to request grooming of specific areas on the body.
The findings suggest humans' closest living relatives may be capable of mental-state attribution, making inferences about the knowledge of others.
Up until now, scientists saw directed scratching only in captive chimps and language-trained apes interacting with humans.
"The more we learn, the more we see chimpanzees employing remarkable, seemingly human-like behaviors," Mitani said.
The research appears in the journal Current Biology, in a paper entitled "Referential Gestural Communication in Wild Chimpanzees."
Copyright 2006 by United Press International