On Christmas Day 1859, a shipment of 24 rabbits from England arrived in Melbourne, Australia. The rabbits were a gift to Thomas Austen, a wealthy English settler who aimed to establish a colony of the creatures on his Australian estate. He accomplished that – and then some.
Just 3 years later, thousands of his European rabbits (Oryctolagus cuniculus) were walking around. By 1865, Austin boasted to local papers that he had killed nearly 20,000 rabbits on his estate, where he hosted rabbit hunting parties for English royalty such as Queen Victoria’s son, Prince Alfred.
Austin wasn’t the first to bring down the rabbit. Five animals were aboard the first fleet of British ships to reach Sydney in 1788, marking the beginning of the introduction of around 90 rabbits to Australia’s east coast over the next 70 years. Yet Austin’s rabbits came to dominate the continent, a new study finds. About 200 million rabbits now wreak havoc on crops and native plants, causing $200 million in agricultural losses annually. And almost all of them, the researchers concluded, can be traced back to the fateful shipment Austin received in 1859.
To find out how rabbit plague started, Cambridge University geneticist Francis Jiggins and his colleagues analyzed the genetics of 187 rabbit samples collected across Australia. They also tested potential source populations in England and France and a handful of rabbits in Tasmania and New Zealand, places that have experienced their own devastating rabbit attacks.
Most of Australia’s rabbits, apart from two local groups around Sydney, share a common gene, the team reported today. Proceedings of the National Academy of Sciences. The rabbit genome also revealed that the epicenter of the attack was near Austin’s estate in Victoria. As the rabbits spread away from the site, the population became less genetically diverse, resulting in a homogenous population of rabbits. What’s more, the researchers pointed out many genetic similarities between Australian rabbits and rabbits in southwest England, where Austin’s family collected the first group of rabbits to ship to Australia. Researchers have concluded that Australia’s ongoing rabbit outbreak began when Austin released an initial shipment of 24 rabbits on his property.
Genetics gave clues as to why this population was primed for invasion. Accounts of earlier Australian rabbits mention floppy ears and fancy colored fur, two characteristics common 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 largely wild ancestry, genetic analysis revealed.
The historical record supports this. Austen family letters and lore reveal that Austen’s brother sent many wild-caught rabbits to Australia in addition to domesticated bunnies. During the 80-day boat trip, the rabbits began to interbreed.
Austin’s rabbits had another advantage over their predecessors: they arrived in the more forgiving Australian environment. When the former rabbit newcomers ventured out into the bush, they encountered strange plants and many carnivorous reptiles, marsupials and dingoes. But by the mid-19th century, the outback had been converted to pasture, and livestock began to be hunted by hunters to protect them. “It was like a perfect storm,” says co-author Joel Alves, an evolutionary geneticist at the University of Oxford.
The Australian landscape is still struggling with the aftermath of this storm. After the rabbits escaped from Austin’s estate, they spread more than 100 kilometers per year, despite stress from viruses such as rabies and smallpox. Engineered to eliminate them. In just 50 years, the animals had colonized an area nearly 13 times larger than their original European range, a faster rate than any other mammal, including pigs and cats.
And they continue to breed. “It’s like faulty brakes 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 continent around the same time as Austin. In 2018, Peacock co-authored a study showing that rabbit infestations were spread by multiple rabbit introductions.
But he applauds efforts to ignore the origins of Australian rabbits, saying they could help efforts to create more targeted pathogens to control and potentially eradicate rabbit populations. “The better [we understand] origin, spread and genetics, we can manage Australia’s most serious pests.”