For the longest time, everyone just assumed giraffes were mute. It made sense, honestly. You watch them at the zoo or on a safari in the Serengeti, and they just glide around like giant, silent ghosts of the savannah. They don't roar like lions. They don't bray like zebras. They just chew.
But here’s the thing: they aren't silent. Not even close.
If you’ve ever wondered what does a giraffe sound like, the answer used to be "nothing." Even biologists were stumped for decades. They thought the giraffe's neck was simply too long to produce the necessary airflow for vocalization. It’s a long way from the lungs to the mouth—about 13 feet in some cases. People figured the physical effort required to push air through that massive trachea was just too much work for a simple "hello."
We were wrong.
The Mystery of the Low-Frequency Hum
In 2015, a team of researchers from the University of Vienna, led by Angela Stöger, decided to actually investigate this. They spent almost 1,000 hours recording giraffes across three European zoos. They gathered nearly 950 hours of audio data. What they found changed how we view these animals forever.
They don't talk during the day. That’s why we missed it.
When the sun goes down and the predators start prowling, giraffes start humming. It’s a low-frequency sound, right on the edge of what human ears can perceive. It’s a deep, rhythmic "ummm" that sounds a bit like a monk chanting or a very distant idling truck.
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Why the Nighttime Serenade?
Why wait until dark? It’s likely a safety thing. Giraffes have incredible eyesight, so during the day, they use visual cues to keep the herd together. They can see a flick of a tail or a turn of a head from miles away. But at night? Night is dangerous. They can’t see each other as well, and they need a way to say, "Hey, I’m still here," without alerting every lion in a five-mile radius.
The hum is incredibly low—around 92 Hertz. For context, that’s a deep bass. It’s not quite infrasonic (sounds below the range of human hearing), but it’s close. Because it’s so low, it travels well through the night air, allowing the herd to maintain a "contact call" without making a spectacle of themselves.
It’s Not Just Humming
If you get close enough—and I mean dangerously close or in a controlled veterinary setting—you might hear the other side of the giraffe's repertoire. They aren't restricted to just that weird, ghostly hum.
- The Snort: This is usually a "get back" signal. If a giraffe feels threatened or annoyed, they’ll blast air through their nostrils. It’s loud. It’s sharp. You won't miss it.
- The Hiss: Usually seen in mothers protecting their calves. It’s a warning.
- The Burst: Sometimes, they let out a short, high-pitched scream or a "waa" sound. This is rare and usually associated with extreme distress or a calf calling for its mother.
- The Cough: Giraffes actually cough to signal submissiveness or even attraction during mating rituals. It’s dry and raspy.
Basically, they have a toolbox of sounds, but they’re just incredibly disciplined about using them. They are the introverts of the animal kingdom.
Why We Thought They Were Mute for So Long
Scientists used to point at the giraffe's anatomy as proof of their silence. There was a long-standing theory that because the laryngeal nerve (which controls the voice box) has to travel all the way down the neck, around the aorta, and back up to the throat, the "signal lag" or the sheer length made complex vocalization impossible.
This is actually a famous example used in evolutionary biology to show "unintelligent design." The nerve is way longer than it needs to be. In a giraffe, that nerve can be 15 feet long!
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But nature is resourceful.
Just because the hardware is awkward doesn't mean the software doesn't work. The Vienna study proved that giraffes have the lung capacity to power these sounds; they just choose their moments carefully. They use their massive chests like bellows to push air through that long "flute" of a neck.
The Acoustic Complexity of the Savannah
Imagine you are a giraffe. You’re six feet tall at birth. You grow to eighteen feet. Everything wants to eat you when you're young. If you spent all day shouting like a kookaburra, you’d be dead in a week.
Silence is a survival strategy.
When we ask what does a giraffe sound like, we are really asking how they communicate. It turns out they are masters of non-verbal language. They use their ears, their tails, and their positioning. But that hum—that low, vibrating drone—is the glue that holds the herd together when the lights go out.
Interestingly, researchers are still debating if there is an infrasonic component to their speech. Elephants use infrasound to talk over huge distances. Some scientists, like Elizabeth von Muggenthaler, have suggested giraffes do the same. While the 2015 study didn't find definitive proof of infrasound, many experts still believe it’s possible. The sheer size of their larynx suggests they could be making sounds we simply cannot hear without specialized equipment.
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How to Hear One Yourself
You probably won't hear a giraffe hum at your local zoo during a 2:00 PM feeding. It’s too loud. There are children screaming, popcorn popping, and wind rustling. To hear what a giraffe sounds like, you need absolute silence and a very high-quality parabolic microphone. Or, you need to be a zookeeper pulling an overnight shift when the barn is dead quiet.
Even then, it’s subtle.
If you look up recordings from the University of Vienna study, you’ll notice the sound is haunting. It doesn't sound "animalistic" in the way a dog's bark does. It sounds mechanical, almost like a digital interference pattern.
Actionable Insights for Wildlife Enthusiasts
If you’re heading out on a safari or just visiting a sanctuary, don't expect a noisy experience. However, you can "listen" with your eyes.
- Watch the Nostrils: If a giraffe is about to "snort" or "hiss," you’ll see a visible flare and a sharp movement of the chest.
- Observe the Calves: Most audible, high-pitched vocalizations come from the young. If a calf is separated from its mother, listen for a "lost" call that sounds vaguely like a goat's bleat.
- Night Observations: if you are at a lodge with a waterhole view at night, pay attention to the "vibe" of the herd. While you likely won't hear the 92Hz hum with your naked ear from a distance, you might feel a sense of rhythmic presence that wasn't there during the day.
- Check Out Citizen Science: Programs like "Giraffe Spotter" or academic databases often host raw audio files. Searching for the Stöger et al. (2015) supplemental data is the best way to hear the actual "hum" without needing a plane ticket to Africa.
The world of animal communication is constantly being rewritten. We used to think whales were just making random noise; now we know they have dialects. We thought giraffes were silent; now we know they’ve been humming under our noses for millennia. It reminds us that just because we don't hear something doesn't mean the world is quiet. Sometimes, you just have to wait for the sun to go down and listen a little closer.
Next time you see a giraffe, don't see a mute giant. See a sophisticated communicator that knows exactly when to keep its mouth shut—and when to sing to its friends in the dark.
Source Reference:
Stöger, A. S., Baotic, A., Liertzer, G., & Gumpenberger, M. (2015). Humming in giraffes: acoustic evidence for vocal communication. BMC Research Notes.