Lar gibbon language may provide insight into the evolution of human language.
Also known as ‘white-handed gibbons’, adult lar gibbons are only about a half-meter tall, and thus, like most primates, including our own genetic ancestors, require means by which they can scope out potential predators, as well as telling others of places where food can be gotten. Of course, primates, including chimps and gibbons, generally use a series of noises to these ends. New research suggests that these noises may provide insight into the evolution of human languages.
Lar gibbons, in particular, have a large ‘vocabulary’ of whooping-type noises, called ‘hoos’ – I assume that’s a scientific term – differentiated subtly by ‘hoo’ pitch (how high-pitched or low-pitched it is) and by ‘hoo’ duration (how long it takes to make). Recent research on the matter, particularly by Durham University of St. Andrews, UK, has finally been able to ‘translate’ the ‘meaning’ of around 450 different types of ‘hoos’, using the same sorts of techniques used by marine biologists to study the even more complex ‘language’ of dolphins.
Interestingly, lar gibbons have a distinct ‘hoo’ for a variety of well-known predators, including tigers, pythons and raptors, such as eagles. Not only that, but ‘related’ predators are assigned similar-sounding ‘hoos’. In other words, lar gibbons seem to have a ‘word’ for ‘tiger’, a ‘word’ for ‘python’, and a ‘word’ for ‘eagle’. Even more interestingly, their ‘words’ for various raptors are all below the optimum hearing frequencies, 1-4 kHz, of most raptors that prey on them.
As well as having a ‘lexicon’ for various predators, as well as other animals in their environment, lar’s also have ‘hoos’ for neighboring gibbon tribes and even for individual gibbons – names, almost. This is getting into the area of ‘dolphin-speak’, and of the origin of human language.
Comparing animal calls
One can hypothesize a smooth transition from base-line calls made by most animals (a handful of calls for a handful of important situations), to that of most primates and canines (the base-line set plus a small ‘vocabulary’ of calls used for acquiring food and/or calling out threats), to that of Lar Gibbons (base-line + alerts + hunting + ‘words’ for individuals and animals), to that of dolphins (base-line + alerts + hunting + ‘words’ & ‘names’ for individual dolphins as well as other animals and even simple actions), and finally to that of human language – with the formation of sentences and the ability to create wholly new words for new things.
It would be exceedingly interesting, for me anyway, if linguists, primatologists, marine biologists, and maybe other biologists as well, could get together and compare the calls of dolphins and other cetaceans such as whales, of primates, and of various other animals to human language – and then to create an inter-species ‘dictionary’ of sorts. Who knows what revelations may come out of such research!
Do you want to hear the ‘hoos’ of lar gibbons for yourself? Check out the sound gallery.
Clarke, E., Reichard, U., & Zuberbühler, K. (2015). Context-specific close-range “hoo” calls in wild gibbons (Hylobates lar) BMC Evolutionary Biology, 15 (1) DOI: 10.1186/s12862-015-0332-2