It's interesting that the Bunyip achieved the same result the Loch ness monster did. Stopped kids playing in dangerous water ways, stopped people using the natural boundaries the water way was, to sneak up.
http://en.wikipedia.org/wiki/Bunyip
Hate to break it to you, but the Loch Ness monster doesn't exist, never did, and neither does a Bunyip.
Although, indigenous civilization is so old they were here when larger roos and wombats roamed, science has shown. Chances are there is some truth to the stories.
Yep, possibly played a large part in the decline of Australia's megafauna from that era too. Diptrodon australis would have been an awesome sight; unfortunately it could have easily had the nickname "walking roast on 4 legs", as it wouldn't have stood much chance against such expert hunters. Plus Procoptodon and Palorchestes as well.
Did Australia's extinct megafauna influence their cultural stories? Sounds reasonable. Does that make their myths real? No, it doesn't.