Unfortunately the Australian bush is unforgiving of mistakes, the US has bears, here just the isolation can be a killer with a lot of areas without phone coverage if something goes wrong, In my area there is threats from snakes and there have been a few instances of attack by dingo packs, including dragging kids out of open tents. I am mostly to far south for crocodiles, but there have been sightings in the local river. If you get into trouble you need to be self reliant as rescue may take time with rescue personnel walking in or using helicopter. 4x4 rescue is only an option along the beach. The Cooloola national park has a thick canopy and undergrowth. It is all growing on sand, just like Fraser island a short distance away. With it all being world heritage listed everything taken in must be taken out, no wood gathering for fires. In @Cate s state you see people needing rescue every year due to being unprepared for the cold rugged terrain.
A couple of pics from Carlo Sandblow in Cooloola National Park, I don't have any pics of the interior of the park handy, as they have been archived on an external hard drive.
I hope the break helps. How was your hike?