ST. ANDREWS, Scotland, Dec. 29 (UPI) -- Chimpanzees can sense when others in a group are unaware of a present danger and can issue warnings, European researchers say.
The findings suggest chimpanzees are aware of the information available to other chimpanzees and make decisions about the messages they choose to convey based on that understanding, the researchers report in the journal Current Biology.
"Chimpanzees really seem to take another's knowledge state into account," Catherine Crockford of the University of St. Andrews in Scotland said. "They voluntarily produce a warning call to inform audience members of a danger that they do not know about. They are less likely to inform those who already know about the danger."
The study challenges the notion that only humans recognize ignorance in others and take steps to inform them, the researchers say.
The findings may shed light on the evolution of language, they say.
"Some have argued that a crucial stage in this evolution occurred when individuals began producing vocalizations with the goal of informing and thereby reducing ignorance in others," Crockford said.
The findings show "more of the 'essential ingredients' needed to kick-start complex communication are evident in chimpanzees than we thought," she said.