We all know the telltale hum of a computer's fan kicking on, or the barely-there buzz of flourescent lights. But even the most whisper-quiet devices are singing their little songs of daily life; you just can't hear them. At least not without some help.

Getting microscopic objects into formation is a tricky proposition. They don't make tweezers small enough. Fortunately there's an alternative: sweeping them up in a sonic vortex.

At just five inches long, tarsiers are among the world's smallest primates. And yet they communicate much like humans, using a wide range of calls to communicate. That's why it's so weird that some tarsiers apparently stay completely silent.

If you've ever seen a common domestic mouse, your first thought probably wasn't, "You know, I bet that guy has an amazing singing voice." But it turns out male house mice are rodent crooners, singing ultrasonic love songs to woo females.

China's concave-eared frogs are one of two amphibians that use ultrasonic frequencies to communicate. There's only one small problem: the males and the females have evolved along such vastly separate lines that females are completely deaf to the males' ultrasonic cries.

Squirrels. They're rats with fluffier tails, and the little bastards used to steal the peaches off of my grandma's trees while our brilliant but useless dog watched. Sonic repellents are nothing new (for animals or people), but the Mega Sonic Scatter-Cat adds a mega-dose of cheap toy cheesiness, making noise assaults…

You might have heard of the teen-repellent noisemaker a store owner employed in his parking lot in the UK, and now that squealing device that supposedly makes an extremely annoying racket that only teens can hear has found its way to the United States. The device has been named Kids Be Gone, as if paying customers…