The didgeridoo is a long wooden wind instrument traditionally made from eucalyptus branches hollowed out by termites. Its deep, resonant drone has been used for millennia by the Aboriginals in ceremony, storytelling, and musical performances. Additionally, numerous didgeridoo players could form rudimentary long-range communication systems; variations in rhythm, pitch, and overtones could convey coded messages across several kilometres, particularly in open plains and coastal areas.
Didgeridoos were also employed historically to convey military orders to troop formations alongside drums, much like Europeans used bugles and trumpets.