The didgeridoo (also spelled Didjeridu), is possibly the oldest wind instrument in the world. It is a tree or limb that is naturally hollowed out by termites, who eat the dead (heartwood) part of the tree. It is used for ceremony, celebration, healing, stories, and to connect the aboriginals to their ancesters in the dreamtime.

In modern day it has evolved into a versatile musical instrument. It is used for healing, meditation, rhythm, and is played in all styles of music. "Non-aboriginal people first documented encountering the didjeridu when an explorer named T.B. Wilson described an aboriginal man playing an instrument called the eboro in Raffles Bay on the Coburg Peninsula in 1835. He described the instrument as being made of bamboo and about three feet in length. The earliest references to the instrument all occur in the later part of the last century. In the century that followed, the instrument was observed by anthropologists on mainland Arnhem Land.

The hard wood instruments particular to Arnhem Land (yirdakis) were usually crafted from eucalyptus species like "stringy bark" and "woolybutt" in the North, and Red River Gum further south near Katherine. There is also documentation of didgeridoos made of palm even further south. By the time anthropologist Alice Moyle was publishing her field work in the mid 1970s, aboriginal groups where using found pipes such as land rover tailpipes and water pipes as didgeridoos.

Source: Sacred Hollow Didjeridus