Everyone knows about those weird loopy gyroscopes in your head (the semicircular canals). But did you know that your inner ears also contain little sacks of crystals called otoliths that make them accelerometers too?
You can find these little organic sensors in the Utricle and the Saccule of the inner ear.
Any game developer who has had to do any kind of motion tracking/gesture handling will recognize that having gyros and accelerometers works much better for dead-reckoning than using an accelerometer alone to simulate a gyroscope.
So your ear has both. (And you head has two sets of them too). This gives you much better accuracy.
They may let you hear subsonic and ultrasonic sounds too. Yes, I know what you’re thinking – by definition, you can’t hear subsonic or ultrasonic sounds. Absolutely correct, I can’t argue with it. But your body can and does respond to them, even if they don’t get translate into “pitch”.
Handy little blingy things.