What kind of tricks can you do with your ears? Can you wriggle them? Or wave just one at a time?
Or, like most of us, are your ears just sitting there like seashells on each side of your head, passively letting reality pour inside them?
Don't feel bad. Anecdotal evidence suggests only one or two people in 10 have independent ear mobility — apparently, an evolutionary holdover from a time when humans needed to swivel their ears like animals.
If you really want to feel jealous, consider this: There's a select few people who can entertain themselves endlessly, by performing ear tricks only they can enjoy.
It's called ear rumbling.
Recently, an engineer who goes simply by "Massimo" offered an in-depth look at how it works with more than 150,000 followers on Twitter.
"A part of the human population can voluntarily control the tensor tympani, a muscle within the ear," Massimo explains in his post. "Contracting this muscle produces vibration and sound. The sound is usually described as a rumbling sound."
The post brought out a few naysayers ("I've never even heard of this…") a lot of yaysayers ("Awesome!") and even a couple of hey-that's-me-sayers ("Slightly crap super power, but I'll take it!")
But how exactly does ear rumbling work?
Meet the tensor tympani
Well, scientists — not the types to subscribe to Power Ranger nomenclature — call it tensor tympani contraction. That's literally the tightening of a muscle in the ear called the tensor tympani. It flexes on its own when we vocalize, yawn, swallow, laugh or cough. That results in the tensing of the eardrum — and a tense ear drum won't vibrate so much, which in turn muffles sound. All one really hears is the sound of that muscle contracting.
Some people were born with the ability their tensor tympani at will.
But, like ear wrigglers and other ear-crobats, ear rumblers blend in so well with the general population, there's no real sense of how many walk among us — although you might strongly suspect one of them is that colleague who never seems to hear a word you say.
Ear rumblers have a much more pronounced presence on Reddit, where a dedicated community gathers under the banner, Ear Rumblers Assemble.
And in one post, an uber-rumbler describes how he uses his gift for much more than entertaining himself. It gets him through boring and altogether too frequent office meetings.
"I can do it on a whim for long periods of time," Redditor PureFingClass crows. "Usually in a meeting when I want to drown out someone's voice."
It's also possible that more people have the gift of ear rumbling but don't know it yet. Unfortunately, there's no single way to find out if you're among them. People use their own unique methods to tap into their superpower.
"It happens when I contract my face and smush it real hard, my eyes close and my nose scrunches up and I hear this rumbling sound," notes one Twitter user.
Writing for IFLScience, James Felton suggests you proceed thusly:
"If you'd like to find out if you can make this sound, you can try screwing your face up really tightly, including your eyes. Go ahead and try it, don't feel embarrassed, I'm sure nobody is watching. Did you hear it? Most people describe it as a rumbling noise, with some describing it like a thunder."
Well, did you hear it?
Or was that just the sound of the ocean, echoing through the seashells that sit lifelessly on the sides of your head?
In any case, I can't hear you. I'm rumbling.