Y’all, Australia cannot stop going to war with its animals. But it’s never like, war with crocodiles or dingoes, no. It’s goddamn emus and fucking rabbits.
Wars you’d think humans could win, right?
Today’s Moment of Science… Bunny Wars.
What would eventually become Australia was part of the supercontinent Gondwana about 500 million years ago. Then that business smashed into all the other landmasses and for about a hundred million years, became known as Pangea. When it started breaking up about 200 million years ago, Australia got an extra evolutionary wallop. They broke off from Gondwana first, along with India and Antarctica. Fossils from animals isolated to Australia can be found as early as about 120 million years ago.
There’s been a closed system in place for so long that the native plants and animals have largely carved comfortable ecological niches for themselves. Which is also why it doesn’t take the most scary, big, sharp, scratchy of animals to cause a ruckus in Australia. It just has to be one that a hundred million years of carefully honed evolution on the smallest, most isolated continent isn’t ready for.
So, bunny rabbits.
In the late eighteenth century, Britain got the shit kicked out of them by some ungrateful colonists in the Americas, but decided they needed to keep doing imperialism. They went to Australia, saw Aboriginal people, and said “behold, this uninhabited land is ours!” And so they brought over distinctly British things like driving on the left side of the road, criminals, and… rabbits?
Yeah. They came over in the first ships in 1788, but weren’t a problem for a few decades. By the 1820s, a feral rabbit problem popped up in Tasmania, but nobody sent a “maybe no rabbits in Australia” telegram to Canberra. So in 1859, when some guy named Thomas Austin who really fucking loved rabbit hunting wrote home asking for a dozen rabbits? He likely didn’t know he was launching an ecological disaster.
You know how I “joke” about Australia being a country that can fuck up your shit like no other?
It seems the Australian ecosystem wasn’t sure what to do with an animal that lacked a seventeenth nipple in its sphincter that sprayed boiling acid.
An adorable bunny? Pfft, said the giant earthworms and the cassowaries and the venomous monotremes (fuck you, these are all real). Why bother with a plentiful food supply that won’t inflict death on us in a unique and clever way?
The rabbit had no natural predators in Australia. By the early 1900s, millions of them were running free across the Australian outback.
At first, shit was great for rabbit trappers. You wanted rabbit fur or rabbit stew? Fed and clothed, baby. But if you were trying to grow crops, those bunnies gave nary a fuck that you had hungry Australians to feed. They decimated fields, leaving dust in their wake.
To combat the rabbits, they built fences; the bunnies dug under them. They rounded them up by the thousands and had cullings; it helped, but the population always grew back. They got a small ferret army to do battle with the rabbits; do you know how many ferrets it would take to end that many millions of bunnies? Enough ferrets that we’d have a ferret problem.
A virus called myxomatosis was discovered that wiped out rabbit populations. It wasn’t without controversy to do biological warfare with the bunnies. There was suspicion that it could cause disease in humans (the disease only affects rabbits). Field trials started in 1937, showing it could successfully- and safely- control the rabbit population. Only after a rough year of being plagued by rabbits in 1949 was the bunny bioweapon introduced into the wild in 1950.
After myxomatosis was deployed, the rabbit population was decimated. Finally, the war with the rabbits was at a ceasefire.
But it wasn’t a lasting peace.
The thing about a virus killing 99.8% of the species is that if you have millions of them, even if only 0.2% live? If a genetic quirk gave them immunity, they’re gonna pass on those genes. And there’ll be a lot of years with fewer bunnies, but a few generations down the line, most bunnies will be genetically predisposed to laugh in the face of your fancypants biowarfare program.
Now, the calicivirus (which first I heard and thought it was the Khaleesi virus, which… cool) has successfully been added into the program for managing the rabbit infestation. Myxomatosis efficacy has waxed and waned, as we watch this virus evolve in real time. Rabbits get better at surviving the virus, then the virus gets better at killing rabbits. Bunnies, welcome to the Australian evolutionary arms race.
This has been your daily Moment of Science, for some reason hearing Elmer Fudd with an Australian accent.
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