Maybe you hum a little tune while assembling a sandwich, and maybe even contentedly between good bites. You wouldn’t be the only one on the evolutionary family tree to do so—so do our cousins, the great apes. Specifically, a set of western lowland gorillas in the Republic of Congo. A recently released pair of recordings of their meal-time vocalizations, courtesy of New Scientist, make me very happy:
Dig beneath the ambient jungle noise of birds and foliage cracking and you will hear, very faintly, what sounds like a potbellied silverback rubbing his tummy and firing off a string of contented scatty hums. That’s a gorilla I want to hang out with, have a banana with. You know, just unwind. This next one, a fuzzed-out rumble, feels even more satisfying, like the ominous bass intro to a Rage Against the Machine banger.
Primatologist Eva Luef, who observed these apes in the wild, said the gorilla sounds could be sorted into these two categories: a string of short differently pitched notes, or one deep, sustained note. The apes tended to improvise new tunes, like freewheeling jazz apes, rather than sticking to their old favorites. “They don’t sing the same song over and over,” says Luef. “It seems like they are composing their little food songs.”
Apparently only the dominant males vocalized in this way, suggesting to the researchers that, aside from signaling satisfaction, these sounds might double as a way of communicating directions to the group, along the lines of it’s still meal-time, we’re not going anywhere yet. Some believe that studying animal food calls, in their variation across species and environments, can teach us about the origins of meaning in signals, and, by extension, the origins of language itself.