Actually, I don’t know the answer. Somehow, after Australia’s early split from the mainstream evolutionary process, our animals decided to go for poison rather than sheer muscle as a defence. Crocodiles being the exception, we don’t have much in the way of big, scary things that are hell-bent on ripping your head straight off with their fangs and dragging your carcass off to a cave for morning tea. No big cats or bears down here. You are actually reasonably safe walking through the Australian bush. The crocs are only way up north, and even then can be avoided if you do your homework. Most of our bitey, scratchy, itchy poisonous things are timid. Stay out of very long grass, don’t go rummaging around piles of dead wood, or sticking your fingers into holes in the ground, and you’ll be fine.
My first hypothesis was that it was because it wasn’t inhabited by humans until relatively recently, and even then it didn’t have a very high population. It stands to reason that people try to kill off things that can sneak into your tent and kill you…but then I remembered that Australia has probably been inhabited at least as long as the Americas, which don’t seem to have too many deadly poisonous creatures.
Maybe…but no parts of me have died and fallen off after bites, and I get at least 3 or 4 a year. However, there are also at least a dozen type of wolf spiders.
