This Didgeridoo is an entry model which I bought in Melbourne in 2004. It is hollowed by drilling through the wood. The traditional didgeridoo is hollowed by termites. One of the key techniques used by the Didgeridoo players is the circular breathing.
History of the Didgeridoo^
The didgeridoo is a wind instrument developed by Indigenous Australians of northern Australia potentially within the last 1500 years and still in widespread use today both in Australia and around the world. It is sometimes described as a natural wooden trumpet or drone pipe. Musicologists classify it as a brass aerophone.
A modern didgeridoo is usually cylindrical or conical and can measure anywhere from 1 to 3 metres long. Most are around 1.2 metres long. Generally, the longer the instrument, the lower its pitch or key. However, flared instruments play a higher pitch than unflared instruments of the same length.
https://en.wikipedia.org/wiki/Didgeridoo (retrieved on 26 September 2017)