It's hard to believe that this video of a cassowary is real, and that these giant flightless birds (which look like emus, also called the "world's most dangerous bird") actually sound like this. It's true though—cassowaries have incredibly deep voices that can reach frequencies as low as 24Hz. Wild Ambiance explains that these low-frequency sounds:
carry a significant distance and are no doubt an effective way for cassowaries to communicate in dense rainforest.
I originally found this video posted in two different Reddit communities I'm part of (both of which I highly recommend). Over on r/InterestingAsFuck ("For anything truly interesting as fuck"), commenter Ardes_ provided more information:
What this video doesn't give you is the resonance effect its voice has on your body. A cassowary's voice is so deep, it literally makes your body's chest cavity vibrate along with any loose clothes you may be wearing, like if you've ever stood next to a giant, deep-sounding drum or musical instrument when it's being played. …Only this is way more terrifying because it's coming from a dinosaur ancestor that can shred you open in one swipe. Meeting one at the Australia zoo is an experience I'll never forget.
And in the subreddit r/NatureisFuckingLit ("We are here to appreciate the awesome majesty and incredibly cool aspects of nature. 🔥"), this comment by Sebelzeebub made me laugh out loud:
The Cassowary and me sucking the last bit of smoothie up with my straw sound the same.
To hear more cassowary sounds, check out this terrific footage by Wild Ambience, a Sydney, Australia-based professional nature sound recordist who provides this description of their work: "I am a professional nature sound recordist and my work is regularly used in wildlife documentaries, films, musical compositions, museum exhibits, sound art installations." Here's how they describe the cassowary sounds they captured:
The call of the cassowary is the lowest frequency sound made by any bird and borders on infrasound. To appreciate the power of the sounds in this video, you'll need decent speakers or headphones – speakers on a mobile device or laptop will not transmit these frequencies. More of a non-vocal sound than a 'call', Southern Cassowaries create this vibrating, booming rumble from deep within. With head tilted down toward the ground, its whole body shudders as the sound is produced. When you hear this sound in real life, you 'feel' the sound as it vibrates through the air. It sounds more like a noise made by a large mammal than a bird.
