I seem to remember hearing about a wild horse 'Brumby' problem years ago, although nothing recently.
Hopefully they got some kind of handle on them.
Pretty much all these hard hooved large animals are descendants of those left behind by failed settlers, etc.
Camels, horses, long horned cattle, as well as rabbits, foxes, cane toads etc were all introduced.
Please don't get me started on the introduced plant pests
