On Christmas Day 1859, a shipment of 24 rabbits arrived in Melbourne, Australia, from England. The bunnies were a gift to Thomas Austin, a wealthy English settler who intended to establish a colony of the creatures on his Australian estate. He achieved it – and then some.
Just 3 years later, thousands of his European rabbits (Oryctolagus cuniculus) were dancing around. By 1865, Austin would boast to the local newspaper that he had killed around 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 person to bring rabbits Down Under. Five of the animals were on the first fleet of British ships that arrived in Sydney in 1788, the start of nearly 90 rabbit introductions along Australia’s east coast over the next 70 years. However, it was the Austin bunnies that dominated the continent, a new study finds. An estimated 200 million rabbits now wreak havoc on crops and native plants, causing $200 million a year in agricultural damage. And almost all of them, the researchers conclude, can be traced back to the fateful shipment that Austin received in 1859.
To find out how rabbit plague started, Francis Jiggins, a geneticist at the University of Cambridge, and his colleagues analyzed the genetics of 187 rabbit specimens collected across Australia. They also tested potential source populations in England and France and a handful of rabbits from Tasmania and New Zealand, countries that experienced their own devastating rabbit invasions.
Most of Australia’s rabbits, apart from two contingents located around Sydney, shared a common ancestry, the team reports today in Proceedings of the National Academy of Sciences. The rabbit genome also revealed that the epicenter of the invasion was near the site of Austin’s property in Victoria. As the bunnies spread further from the country, the population became less genetically diverse, resulting in a homogenous population of rabbits. In addition, the researchers noted some genetic similarities between Australian rabbits and bunnies in southwest England, where Austin’s family raised the first batch of rabbits to be shipped to Australia. The researchers conclude that the ongoing rabbit disaster in Australia began when Austin released the initial load of 24 rabbits on his property.
Genetics provided clues as to why this population was primed for invasion. Accounts of early Australian rabbits mention floppy ears and ornately colored fur, two common traits in domesticated rabbits, suggesting they may have been too domesticated to adapt to Australia’s wild landscape. But the Australian rabbits descended from Austin’s litter had a large amount of wild ancestry, the genetic analysis revealed.
Historical records support this. Austin family papers and lore indicate that Austin’s brother sent several wild-caught rabbits in addition to domesticated bunnies to Australia. The rabbits began crossing during the 80-day boat trip.
Austin rabbits had another advantage over their predecessors: They arrived in a more forgiving Australian environment. When the early rabbit newcomers ventured into the bush, they encountered strange plants and a host of carnivorous reptiles, marsupials and dingoes. But by the mid-19th century, the outback was being converted to pasture and predators were hunting to protect the livestock. “It was like a perfect storm,” says co-author Joel Alves, an evolutionary geneticist at the University of Oxford.
Australia’s landscape is still struggling with the aftermath of this storm. After the rabbits escaped from Austin’s property, they spread more than 100 kilometers a year, regardless of fences and strains of pox virus. designed to erase them. In just 50 years, the animals had colonized an area roughly 13 times the size of their native European range, a faster rate than any other introduced mammal, including pigs and cats.
And they continue to multiply. “It’s like a faulty brake on a car,” says Alves.
However, 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 Austin. In 2018, Peacock co-authored a study that asserted that the rabbit invasion was driven by multiple introductions of rabbits.
But he welcomes efforts to unravel the origins of Australia’s 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, the better we can manage Australia’s most serious pests.”