Gibbons 'sing with soprano technique'
23 August 2012 Last updated at 16:24 BST
Researchers in Japan have discovered that lar gibbons use the same techniques as human soprano singers to make their melodic but piercing calls.
When the apes made calls while in an atmosphere rich in helium, the team analysed the calls' frequencies.
As the team report in the American Journal of Physical Anthropology, the apes were able to control the natural frequencies of their "vocal tracts".
Such control, exemplified by sopranos, was thought to be unique to humans. Jason Palmer reports.