"However, it might be possible that once vision is limited - for example, at nighttime - and they are separated, that they might use vocalizations to keep contact." "Giraffes have excellent vision and use visual signals for communication a lot," she said.
But Stoeger has a hunch the eerie sound is a method of communication - an idea that needs to be verified in future studies, she said. The researchers didn't take videos of the humming giraffes, so it's unclear exactly what the animals were doing at the time. Giraffes sometimes hum at night, a new study finds. Once the sun sets, some giraffes hum an eerie tune that sounds like a creaking ship, they found. Sometimes, the researchers personally recorded the giraffes, but they relied on autonomous recording devices for the longer night recordings.
To investigate, the researchers recorded a total of 22 giraffes at three European zoos - the Berlin Tierpark, the Copenhagen Zoo in Denmark and the Vienna Zoo. But there's inconclusive evidence for this idea, prompting Stoeger and her colleagues to start recording giraffes in an effort to learn more about the noises they make, and whether those noises are used for communication. Or maybe giraffes produce sounds in the infrasonic range - much like the rumble of elephants - that are below the threshold of human hearing, she said. "There have been suggestions that the giraffe's iconic long neck makes vocalization physically impossible, due to the difficulty of sustaining the required airflow from lungs to mouth over such a distance," Stoeger told Live Science in an email. Its content is produced independently of USA TODAY.The giraffe's neck may explain why the animal doesn't say much. Newser is a USA TODAY content partner providing general news, commentary and coverage from around the Web. "Future studies should test in a well established experimental setting whether giraffes are more vocal when visual communication cues are absent," they conclude. Though the researchers couldn't prove the sound is used for communication, they found "suggestive hints" that the hum might serves as a "contact call, for example, to re-establish contact with herd mates." They speculate the hums may be occurring at night because giraffes' typically keen vision is less effective then. The hum isn't infrasound, but it's not exactly easy to hear either Wirednotes the researchers shared the vocalizations with zookeepers, and the sound was unfamiliar to them. They then analyzed the recordings visually, in a process they describe in BMC Research Notesas "time consuming, tedious, and very challenging." They believed the animals might produce "infrasonic vocalizations" - that is, below the level of human perception-and were looking for such low-frequency sounds.Īnd they did indeed find "structurally interesting humming vocalizations" that occurred mainly at night and hovered around 92 hertz in frequency as one New Scientist commenter notes, they sound a little like the Kraken (listen for yourself here). The researchers recorded animals at three European zoos, amassing 947 hours of recordings over eight years.
Though giraffes have a voice box, one line of thought was that due to their long necks it was too difficult for the creatures to generate the airflow needed to "vibrate their vocal folds."īut University of Vienna researchers now say they've determined that giraffes do indeed "produce vocalizations" that may serve as a means of communication. (NEWSER) – What does the giraffe say? For decades it’s been a simple answer: nothing, except for a snort or grunt every now and then.
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