We are all familiar with how the human voice becomes high pitched when inhaling helium from a balloon. Well, helium gas is also a useful tool when studying the vocal techniques of animals because it boosts resonance frequencies and sound velocity.
This study, conducted by the Primate Research Institute at Kyoto University, Japan, demonstrates how the recordings of gibbons, singing under the influence of this gas, uncovers a physiological likeness to the human voice. The recording show that gibbons are able to purposefully change their vocal cords and tract to produce their unique sound. It states that singing gibbons, without fail and with little effort, take on the intricate vocal techniques, which in humans, has only been mastered by professional soprano singers.