I got one of those "did you know" emails, and this interesting "fact" came up. I'd never heard of it.

A duck's quack doesn't echo, and no one knows why

Does anyone have any theories on this? I can't believe no-one has worked out why yet....

Note to Mods: if this isn't in the correct place feel free to move

I'm guessing that it has something to do with the frequency of said quack and that it does echo, it's just that it's too quick to notice.

--Jon

Yep, the mythbusters tested it and that's the conclusion they came to. The echo is so quick, the frequency appears to decline in a roughly straight line rather than reverberating as you might expect from an echo.

Score!! That was just a guess.

--Jon

Cheers I thought someone somewhere would have worked out why - good ol' Mythbusters.

Brainiac too, brought the duck to a long hallway with a good echo, you can hear it. All sound echoes.

There was a show on Animal Planet about this last night and they concluded that a ducks quack DEFINATELY does echo.

There are many noises that we humans cannot hear, because our hearing frequencies are not as adept as most animals. A duck's quack does echo, but since it is either such a low, or high decibel, we are not able to pick it up. For instance, they have a piece of hardware you can put on your car, so that when you drive, it makes a high pitch noise, made to keep animals away from the roads. Obviously, we cannot hear the noise, but it would work well for animals that can to keep them away.

No, the quack's echo is perfectly within our hearing range since we can hear the quack itself. It just occurs so quickly that it fuses into the tail-end of the quack itself and we perceive the echo as part of the original quack.