On Christmas Day 1859, a shipment of 24 rabbits arrived in Melbourne, Australia from England. The rabbits were a gift for Thomas Austin, a wealthy English settler who aimed to establish a colony of creatures on his Australian estate. He accomplished that, and more.
Just 3 years later, thousands of his European rabbits (Oryctolagus cuniculus) hopped. In 1865, Austin boasted to the local newspaper that he had killed some 20,000 rabbits on his property, where he organized rabbit hunting parties for English royalty like Queen Victoria’s son, Prince Alfred.
Austin wasn’t the first person to bring bunnies Down Under. Five of the animals were on board the first fleet of British ships to reach Sydney in 1788, the start of around 90 introductions of rabbits along Australia’s east coast over the next 70 years. Yet Austin’s rabbits are the ones that have ruled the continent, according to a new study. About 200 million rabbits now wreak havoc on native crops and plants, causing $200 million a year in agricultural damage. And nearly all of them, the researchers conclude, can be traced back to the fateful shipment Austin received in 1859.
To find out how the rabbit plague started, Francis Jiggins, a geneticist at the University of Cambridge, and his colleagues analyzed the genetics of 187 rabbit specimens collected from across Australia. They also tested potential source populations in England and France and a handful of rabbits from Tasmania and New Zealand, places that have seen their own devastating rabbit invasions.
Most Australian rabbits, with the exception of two contingents located around Sydney, shared a common ancestryreports the team today in the Proceedings of the National Academy of Sciences. The rabbit genomes also revealed that the epicenter of the invasion was near the site of the Austin Estate in Victoria. As the rabbits moved away from the site, the population became less genetically diverse, resulting in a homogeneous horde of rabbits. Additionally, researchers identified several genetic similarities between Australian rabbits and rabbits from South West England, where Austin’s family collected the first batch of rabbits to be shipped to Australia. Researchers conclude that the ongoing rabbit plague in Australia began when Austin let the first shipment of 24 rabbits loose on his estate.
Genetics gave clues as to why this population was ripe for invasion. Earlier Australian rabbit accounts mention floppy ears and fancy colored fur, two common traits in domesticated rabbits, suggesting that they may have been too tame to adapt to Australia’s wild landscape. But the Australian rabbits from Austin’s brood had a large amount of wild ancestry, genetic analysis has revealed.
The historical record confirms this. Austin family letters and lore reveal that Austin’s brother sent several wild-caught rabbits in addition to domestic rabbits to Australia. The rabbits started crossing paths during the 80-day boat trip.
The Austin Rabbits had another advantage over their predecessors: they arrived in a more forgiving Australian environment. When the old newcomer rabbits ventured into the bush, they encountered strange plants and a multitude of carnivorous reptiles, marsupials and dingoes. But by the middle of the 19th century, the hinterland was turned into pasture and predators were hunted to protect the livestock. “It was like a perfect storm,” says co-author Joel Alves, an evolutionary geneticist at the University of Oxford.
The Australian landscape is still grappling with the fallout from this storm. Once the rabbits jumped outside the Austin estate, they spread more than 100 miles a year despite fences and strains of pox virus. designed to eliminate them. In just 50 years, the animals had colonized an area about 13 times larger than their native European range, a faster rate than any other introduced mammal, including pigs and cats.
And they keep reproducing. “It’s like a bad brake on a car,” says Alves.
Still, not all scientists blame Austin alone for the rabbit plague in Australia. David Peacock, an ecologist at the University of Adelaide, says other rabbits were released on the mainland around the same time as the one in Austin. In 2018, Peacock co-authored a study postulating that the rabbit invasion was triggered by multiple rabbit introductions.
But he applauds efforts to unravel the origin of Australian rabbits, saying they could aid efforts to create more targeted pathogens to control and potentially eradicate rabbit populations. “The best [we understand] origin, spread and genetics, the better we can manage Australia’s most serious pests.