Theory of Mind in Chimps

The BBC reports that researchers have uncovered a behavior in chimps which displays their consideration of external audiences. The test pitted chimps against a dangerous prey (a rubber snake) and observed the chimps' alerting others to the presence of the predator.

The alert, though, only came if the other chimp did not know about the rubber snake. So, the chimps were apparently considering their own knowledge of the environment and comparing this to the supposed knowledge of other chimps. If the chimp determined that the other chimp did not have the same knowledge about the snake, the first chimp offered an alerting sound.