Ask anyone to do an elephant impression, and they’ll probably all do the same thing: put their arm to their face like a trunk and make a loud trumpet noise.
Elephants are famously loud and low-pitched – sometimes so low-pitched that humans can’t even hear them – and that makes sense for an animal that can weigh up to 7 tons. It just wouldn’t feel right if an elephant went around talking at a human pitch – or worse, squeaking. No, squeaks are strictly the purview of the elephant’s "natural enemy", the mouse. Not the majestic elephant... right?
Well, according to new research published in BMC Biology, we’re going to have to rethink our ideas of elephant elocution. Elephants squeak – and, until lately, that made no sense.
“The following rule generally applies to sound production in mammals,” explained a statement from the research team behind the new pachydermal paper, “the larger the vocal fold, the lower the calls fundamental frequency.”
“Conversely,” it continued, “the size of the vocal folds sets an upper limit to the fundamental frequencies that can be reached.”
In other words: elephants ought to be too big to make high-pitched noises. And yet, the paper notes, Asian elephants squeak when they’re scared – and we really mean “squeak”, as the mammoth mammals can reach as high as 2300 Hz.
So essentially, the question is: what gives? Scientists have known that elephants squeak and chirp for ages, but just how these noises were made has been rather mysterious. The two most likely hypotheses were either that elephants, like microbats or koalas, had some specially developed vocal fold tissue that enabled them to make the weird (for an elephant) noises, or that they were forcing air through some small orifice to make the sound – a process you may know as “whistling”.
So the team set up a study – and a pretty cool study at that. They filmed elephants using an “acoustic camera” that visualizes sound using color – imagine a thermal imaging camera, but instead of heat, you’re looking at sound waves.
Watching the resulting videos, the researchers could see exactly where the noise was coming from.
“Our results strongly suggest that Asian elephants force air from the small oral cavity through the tensed lips, inducing self-sustained lip vibration,” explained the paper. “Besides human brass players, lip buzzing is not described elsewhere in the animal kingdom.”
That’s right: ironically, it’s an elephant’s squeak, and not its trumpet, which is similar to an actual trumpet. The brass instrument makes its tell-tale honk when a player puffs up their cheeks full of air and blows through tightly-tensed lips, doing something halfway between whistling and blowing a raspberry. And according to the study, it is this action – minus the trumpet, for now – that the elephants are doing to make their squeaks.
But here’s where it gets really interesting: the scientists studied 56 elephants for their research, and only 19 of them squeaked. The researchers hypothesized that the animals, which are highly social and emotionally intelligent, might learn how to squeak from their families and their herd. The elephants in the study were all captive, with only a few mother-calf pairs, so most of the kin-bonds they would have in the wild were broken. The 37 non-squeaky elephants, the researchers suggested, might simply have not had anybody to teach them the squeak technique. And if you think that hypothesis sounds farfetched, just remember: at least one elephant is on record as having picked up Korean from his trainer – and that’s a lot harder than just blowing a raspberry or two.