There have been reports of up to 2 million feral Camels in Oz, and apparently they are the purest breeds in the world. I have not shot any, so I do not know how hardy they are.
I believe that there are moves to open Camel Abbitoir's up to export the meat back to the Arabs.
They inhabbit mostly the land west of the Adelaide, to Darwin Road, the Stuart Highway, and numbers have ben spotted even more east of that road, as they look for food and water.
In 2009, after we got back from our Western Australia desert trip, they invaded the Aboriginal Community of Docker River, in their hundreds, looking for food and water..
In thick vegitation on our trip, they just appeared out of nowhere, and they are "friggin huge"