Now, I may be wrong on this Chaz, but going back to your comment on North American snakes and gators:
I'm pretty sure Australia also has 6 of the world's 10 most venomous snakes. And Salt Water Crocodiles are much, MUCH bigger than fresh water alligators.
Really, its no wonder the British used it as a prison. How anyone survived on that island back then I have no idea.
****EDIT:
There's a reason why it started off as a penal colony...
Didn't see you wrote that. EDIT******
Oh, no wait. Just looked it up. SEVEN of the world's 10 most venomous snakes live there. And yet more people die per year from bee stings from European honeybees (around 10/year). Huh.
Anyway, I'm glad I live in Southern Canada where my biggest concerns are coyotes, owls, and occassionall lynx, wolves and brown bears. I don't have to worry about all your crazy venomous stuff.