In the song Waltzing Matilda - What is a Jumbuck

A sheep

"Waltzing Matilda" is Australia's most widely known bush ballad. A folk song, the song has been referred to as "the unofficial national anthem of Australia".

The title is Australian slang for travelling by foot with one's belongings (waltzing, derived from the German auf der Walz) in a "Matilda" (bag) slung over one's back.

The song narrates the story of an itinerant worker, or "swagman", making a drink of tea at a bush camp and capturing a sheep to eat.

When the sheep's owner arrives with three police officers to arrest the worker for the theft, the worker commits suicide by drowning himself in the nearby watering hole, after which his ghost haunts the site.

http://en.wikipedia.org/wiki/Waltzing_Matilda