Sea wasp
Despite the glorious semi-tropical climate, nobody swims at beaches in the northern half of Australia from September to May. For there, all but invisible as it cruises in the calm tropical shallows, is the world's most dangerous marine stinger - the chironex jellyfish, or sea wasp. It is blamed for the deaths of more than 60 people last century, exceeding the combined toll taken in the same region by sharks and crocodiles. The stinging tips are astonishingly tiny and densely packed: more than 1000 venom-injecting threads can be fired from an area about the size of a pinhead. In total, each sea wasp has thousands of millions of these threads. A serious sting can kill within seconds. A less serious one results, at very least, in tissue destruction and horrendous subsequent scarring.
Funnelweb spider
Rearing up, with beads of venom already glistening at the tips of its massive fangs (which are capable of biting through a leather boot), a big funnelweb spider is an unnerving sight. The threat is no bluff. The monster will attack on sight, and until an antivenin was finally discovered in the mid-1980s, dozens of people living in the city of Sydney were killed, including one victim who died in just 15 minutes.
Fierce snake
Venom yielded in an average milking of a big fierce snake could kill 250,000 mice, making it by far the most potent land snake venom in the world. When they strike, fierce snakes snap repeatedly, pumping venom time after time, and can kill an adult in less than 10 minutes. There are another 20 snakes in Australia capable of killing a human being.
Blue-ringed octopus
Stranded in rock pools after big tides anywhere on Australian coasts, the blue-ringed octopus is a common sight. It is just the sort of pretty toy that a toddler will pick up. If not seen, it is tiny enough to be hiding in a can of drink. But it is the most lethal octopus in the world. Its venom includes tetrodotoxin (TTX), a component found in no other creature. Two ducts pass right through its brain, bringing venom down to the mouth from a pair of salivary glands. Each is as big as the brain. Each contains enough venom to inflict paralysis and eventual agonising death on at least ten men.
Cone shell
These beautiful shells can earn collectors thousands of dollars, and so are greatly prized. But they produce and store continuous supplies of disposable poison darts, which can be extended for a distance as long as the shell. When its prey passes close by, the cone shell propels a dart forward, rams it violently against the unsuspecting passer-by, and then draws the paralysed victim back into its snout. The larger species can kill human beings.