As for how Felis catus first arrived in Australia, no one really knows. For a long time, natural historians conjectured that the first cats may have been survivors of Dutch shipwrecks or stowaways with Indonesian trepangers in the 17th century. But genetic tests have now shown that Australia’s mainland cats descended from more recent European progenitors. One researcher, after combing through the records of early European settlements, traced the cats’ arrival to the area around Sydney, the landing site in 1788 of the First Fleet — the flotilla of vessels carrying the convicts and marines who would begin the colonization of Australia by the English. Having been brought to manage rats on the ships, cats made landfall and, by the 1820s, established themselves on the southeastern seaboard. From there, they spread with astonishing speed. “It is a very remarkable fact that the domestic cat is to be found everywhere throughout the dry back country,” one pastoralist reported in 1885. “I have met with cats, some of enormous size, at least 50 miles from water.”
The cats preyed on small animals that interfered with food production or storage. Creatures like the burrowing bettong, or boodie, a rabbit-size cousin of the kangaroo that has clasped forepaws and a bouncing hop, were so plentiful in the 19th century that they were sold by the dozen for nine pence a head. Recipes for curries made with native animals like bandicoots, another small marsupial, appeared in local newspapers. Boodies were, in the words of the naturalist John Gilbert, “one of the most destructive animals to the garden of the settler that occurs in Western Australia,” because of their practice of building interconnected underground warrens. Found throughout central Australia down to the southern tip of the Eyre Peninsula and stretching nearly to the western coast, boodies were one of the most widespread of the continent’s many Lilliputian mammals. Their prodigious digging nearly destabilized railroad tracks in 1908. Then cats were unleashed and, already suffering from disease and fox predation, boodies started to disappear. By the mid-20th century, they were declared extinct in mainland Australia.
It wasn’t just the boodies. If anything, they were lucky — some small groups of burrowing bettongs clung on at a few islands that were relatively sheltered from the ravages visited on the mainland. Since the First Fleet’s arrival, 34 mammal species have gone extinct in Australia. All of them existed nowhere else on earth; they’re gone. More than 100 mammal species in Australia are listed as between “near threatened” and “critical” by the International Union for Conservation of Nature. The continent has the highest mammal extinction rate in the world. Cats are considered to have been a leading threat for 22 of the extinct species, including the broad-faced potoroo, the crescent nailtail wallaby and the big-eared hopping mouse. “Recent extinction rates in Australia are unparalleled,” John Woinarski, one of Australia’s foremost conservation researchers, told me. “It’s calamitous.”
What’s unusual about Australia’s mammal extinctions is that, in contrast to nearly everywhere else, the smaller animals are the ones hit hardest. After the Pleistocene’s wave of species disappearances carried off enormous creatures like saber-toothed cats and woolly mammoths, large mammals all over the world have continued to face pressure, mostly from humans. Globally, it’s rhinos, elephants and gorillas that are among the most threatened. Not in Australia. There, it’s the desert bandicoot, the Christmas Island pipistrelle and the Nullarbor dwarf bettong that have disappeared. They belong to the category of creatures that, Woinarski noted in his seminal 2015 paper documenting the decline, are “meal-sized.”