Source:
http://en.wikipedia.org/wiki/File:Australiandidgeridoos.jpg
The didjeridu (or yirdaki, and several other tribal names) is a horn or large, straight bugle. It has no fingerholes, and produces a drone-like tone.
Source:
http://en.wikipedia.org/wiki/File:Australiandidgeridoos.jpg
The instrument is native to Australia, and was invented perhaps as long as 1500 years ago.
The length of the didjeridu ranges from 1m to 3m, which, due to igts length and larger diameter, results in a lower frequency than instruments such as flutes. The didjeridu is typically made of hollow hard wood.
Playing style is different to that of other horns, using a technique known as circular breathing. A continuous flow of air is achieved by breathing in through the nose while simultaneously blowing air out of the mouth. The mechanics is similar to those of a bagpipe, with the musician's mouth cavity being the "bag".