It’s been a puzzle for quite some time – it’s known that giraffes have a relatively complex social structure, but how is it that they communicate? Oddly, and interestingly, scientists have recently discovered that giraffes in fact hum to each other.
A fantastic article on the New Scientist website digs into the details of the study that was done:
Scientist had earlier speculated that giraffes are unable to produce any substantial sounds because it is physically difficult for them to generate sufficient air flow through their long necks to produce vocalisations. Others have suggested giraffes use low frequency “infrasonic” sounds – sounds below the level of human perception – much like elephants and other large animals do for long-range communication.
After reviewing almost 1000 hours of sound recordings in three European zoos, Angela Stöger at the University of Vienna, Austria, found no evidence of infrasonic communication – but she did pick up a weird humming coming from the giraffe enclosures in all three zoos at night.
“I was fascinated, because these signal have a very interesting sound and have a complex acoustic structure, she says.
The “hum” turned out to be a low frequency sound, of about 92 Hz. That’s not infrasound – we can still just about hear it with our ears. Stöger and her colleagues say the hum varies in duration and contains a rich combination of notes.
It turns out, however, that there is more research that will need to be done to fully understand the exact function of the giraffes’ song. The article continues:
Giraffes have a socially structured system, and for a long time scientists have been trying to figure out how they communicate, says Meredith Bashaw at the Franklin & Marshall College in Lancaster, Pennsylvania. “This new vocalisation could add a piece to that puzzle,” she says.
Bashaw says she can imagine a few potential roles for this humming. “It could be passively produced – like snoring – or produced during a dream-like state – like humans talking or dogs barking in their sleep,” she says. Alternatively, it could be a way for giraffes to communicate with each other in the dark, when vision is limited, to say, “hey, I’m here”, she adds.
Unfortunately, Stöger says she and her colleagues were not able to actually observe the giraffes mid-hum, so we don’t know about the behaviours associated with the sounds. But vocalisations in other species with similar social structure is known to convey information about things like age, gender, sexual arousal, dominance, or reproductive states, she says.
In fact, the article says that some neighbors who live near the zoo have complained about humming sounds coming from the giraffe enclosures, and that those sounds keep them awake at night. Both zoo officials and Stöger contend that the humming could not disturb the zoos’ neighbors:
“No, definitely not linked to our neighbour’s issue – but the image of our giraffes humming happily to themselves all night is a delightful one!” says Phil Knowling, press and public relations officer at Paignton Zoo.
Furthermore, Stöger adds that it is unlikely that the neighbours could hear such humming. “The giraffe signals are not so intensive. I personally doubt that neighbours would hear that,” she says.
Clearly, there’s more research to be done, but we thank the New Scientist for the really interesting article, where you can find even more details about the hum of the giraffes.
Source: NewScientist.com – “Giraffes spend their evenings humming to each other”
Photo Credit: Martin Harvey/Alamy Stock Photo