ANIMALS - Koalas' low-pitched voice explained by unique organ

The pitch of male koalas' mating calls is about 20 times lower than it should be, given the Australian marsupial's relatively small size. Now, researchers have discovered their secret: koalas have a specialized sound-producing organ that has never before been seen in any other land-dwelling mammal. The key feature of this newly described organ is its location outside the voice box, what scientists call the larynx ...

http://www.sciencedaily.com/releases/2013/12/131202121445.ht