Residing in bushes could have given nice apes vocal abilities for consonants

A comparability of consonant-like sounds in nice apes suggests an arboreal way of life could have been a step in direction of complicated speech in our ancestors

By Richard Kemeny

Our complicated speech could have originated from life within the bushes. The primary evaluation of the evolution of consonants suggests their roots could also be linked to an arboreal way of life, hinting that our ancestors spent extra time in bushes than at the moment thought.

All human language makes use of a mix of vowels and consonants to switch info. Most primates talk virtually solely utilizing vowel-like calls, however non-human nice apes produce consonant-like sounds to various levels.

This raises the query of the place consonants come from, says Adriano Lameira on the College of Warwick within the UK. To search out out, Lameira combed by means of current literature to see how frequent consonants are among the many nice apes and if this might make clear their evolutionary origin.

He discovered that wild orangutans, which spend most of their time within the forest cover, produce a larger quantity and number of consonant sounds than wild gorillas, chimpanzees and bonobos, which stay on the bottom. All orangutans produce these sounds, however in different nice apes they aren’t common.

“Orangutans have this rich repertoire of kiss sounds, scrapes and clicks and raspberries and smacks,” says Lameira. They sometimes use these sounds whereas constructing nests, or speaking with their younger, or as alarm calls.

Lameira thinks that residing within the bushes could clarify why orangutans have developed this broad vocal repertoire. Nice apes are adept at extracting hidden or protected meals, like nuts, a ability that usually requires using instruments. Whereas foraging up within the cover, nevertheless, orangutans should all the time use at the very least one arm to keep up stability. They’ve due to this fact developed extra complicated management of their lips, tongue and jaws to make use of their mouths as a “fifth limb” — orangutans can peel an orange simply through the use of their lips, for instance.

As an evolutionary aspect impact, this superior motor ability gave orangutans an elevated skill to supply consonant-like sounds, argues Lameira. This might imply that our early ancestors developed consonant sounds whereas hanging round within the bushes, too.

“There’s a growing sense that our dependency on trees was much larger and deeper than we think,” says Lameira, which fits in opposition to the concept that people began strolling upright as they moved into the savannah. “Within that mosaic that was emerging, we might actually have stayed where the trees were and crossed from one patch to the other as quickly as we could.”

The hyperlink between feeding and vocal communication doesn’t apply to smaller tree-dwelling primates similar to monkeys, says Lameira,as a result of their measurement and their tails make them extra secure on tree branches and so they don’t forage in the identical means.

“The arboreal origin of consonants is an interesting hypothesis worth testing,” says Chris Petkov at Newcastle College, UK, although he questions some elements. He says many monkeys use grunts, that are akin to consonants. And as people aren’t tree-dwelling, there should be different the explanation why consonants persevered, similar to rising social networks driving an enlargement of name varieties. These hypotheses might be examined by characterising consonant-like vocalisations extra systematically throughout species, he says.

“Given that we do not know what led to the evolution of consonants, I think testing this hypothesis can potentially provide some insights,” says Serge Wich at Liverpool John Moores College within the UK. “Of course, we have to remain very cautious that even if there would be a relationship that this does not mean causality as there could be other factors involved.”

Journal reference: Tendencies in Cognitive Sciences, DOI: 10.1016/j.tics.2022.11.012

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