Wild chimps sound alarms for unaware friends

Chimps are more likely to make alarm calls when snake is near when other chimps are unaware of the danger, the new evidence shows.

Humans apparently aren’t the only animals who recognize the knowledge state of their fellows when sounding an alarm for danger. Wild Ugandan chimps do this, too, according to researchers at the the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and the University of St. Andrews, Great Britain.

These researchers say that wild chimpanzees in Uganda are more likely to call an alarm sound indicating a snake is near in the presence of other chimps who are unaware, rather that in the presence of aware group members. Their report was published online on December 29, 2011 in Current Biology.

Chimps are afraid of snakes. This one took refuge in a tree. Image Credit: Roman Wittig/MPI f. Evolutionary Anthropology

The researchers placed model snakes in the paths of wild chimpanzees in Uganda and watched their reactions. When an individual chimp detects a snake, it typically produces an “alert hoo” to tell other chimps within earshot. As new group members arrive on the scene, chimps in the know repeat their “alert hoo” to the unaware chimps, letting the newcomers know that a snake is in their midst.

The findings challenge the notion that only humans recognize ignorance in others and act so as to fill them in, the researchers say. They also show that chimpanzee vocalizations are influenced by a prosocial motivation, to intentionally inform others of danger.

Furthermore, to share new information with others by means of communication represents a crucial stage in the evolution of language, these researchers say, adding that their study thus suggests that this stage was already present when our common ancestor split off from chimps 6 million years ago.

Bottom Line: Humans apparently aren’t the only animals who recognize the knowledge state of their fellows when sounding an alarm for danger. Wild Ugandan chimps do this, too, according to researchers at the the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and the University of St. Andrews, Great Britain.

Via EurekAlert

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