Chimpanzees use distinct sounds to communicate during grooming. Grooming noises such as the lip smack, the teeth clack, and the Bronx cheer are made solely with the lips, tongue, and teeth and not the vocal tract.
Chimpanzee Sanctuary Northwest
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JB, this is immensely interesting! Thanks.
Look how sweet they are to one another! BFF’s
Music to my ears! In your videos you often show Burrito going for the Bronx Cheer and the Teeth Clack, do chimps use all three sounds or is it a ‘personal’ style to use one or two sounds?
Some chimps make more than one sound (like Burrito) while others use only one or make no sounds at all. It’s thought that the production of these sounds is learned, so it probably depends primarily on what sounds an individual is exposed to when they are young, particularly by their mother. Interestingly, while the use of these sounds is learned, there probably is some physiological basis for the mouth movements. Chimps, like humans, tend to make subtle movements with their lips and tongue when engaging in other fine motor movements (picture someone trying to thread a needle and sticking their tongue out to one side). So perhaps the mouth movements were a physiological accident to begin with, but then they became more pronounced as they came to be used as a signal during grooming.
Anyway…most of the chimps at CSNW stick with lip smacking only. There’s actually a fourth sound which some call “lip popping”. It’s like lip smacking expect that a larger amount of air is compressed and expelled during the lip smack. Some chimps do it at the same time as the teeth clack. I didn’t have any video of it and I’m not sure if I’ve ever heard it from these chimps.