For decades, scientists have sought to understand the origins of human language. Research has now revealed that orangutans—a species of great ape found in tropical rainforests—communicate using a complex repertoire of consonant-like calls, more so than their African ape counterparts. This discovery sheds light on how our ancestors may have begun to form the building blocks of language.
A Unique Ability
Previous research has linked the evolution of human language with the voiced-vowel sounds produced by non-human primates. However, human language is composed of both vowel and consonant sounds. It’s now believed that orangutans’ tree-dwelling nature gave them an advantage over ground-dwelling African apes when it comes to communication. When climbing trees, orangutans use their mouth, lips, and jaw as a “fifth hand” for gripping onto branches and other objects. Researchers believe this sophisticated use of their mouths gives them the ability to communicate using a rich variety of consonant sounds.
Testing in Sumatra
Researchers have observed wild orangutan populations in Sumatra over a period of 20 years. During this time they recorded audio samples from over 1,000 orangutan vocalizations. To determine which type of sounds were being used and how often they were used, researchers used spectrographic analysis (a technique used to visualize sound waves). The results showed that orangutans used a wide range of vocalizations with a large number consisting of consonant-like calls made with closed lips and tongues—similar to those heard in human speech today.
These findings suggest that humans may not be alone in our capacity for producing complex speech patterns involving both vowels and consonants—orangutans too are capable of producing these types of sounds! The discovery could help scientists gain more insight into how humans first began to produce speech millions of years ago with our ancient ancestors. Ultimately, understanding what drove us to develop such sophisticated communication skills will give us greater insight into one aspect of what makes us uniquely human!