Orangutans are the only primate apart from humans to cup their hands round their mouths to amplify sounds, a new study says.
As Laura Geggel reports in LiveScience:
When danger nears, orangutans warn their group with alarm calls, and new research shows that the animals sometimes cup their hands around their muzzles, making these calls louder and deeper.
The finding suggests that orangutans know how to change their sounds by using another part of their body, a behavior once thought to be unique to people, according to the international team of researchers. It could be that the animals are trying to make themselves sound larger and scarier when predators are near, they said.
The researchers say that using the hand “appears to be a culturally learned behaviour, and therefore orangutans may be able to associate the acoustic effect of using the hand with potentially more effective deterrence of predators”.
The study was published in the Journal of Experimental Biology.