Two centuries later, they’ve become ecological wrecking balls; killing over 3 billion native animals yearly. Feral cats now roam almost every habitat, from deserts to islands, hunting everything from skinks to wallabies. Their impact? 27 of 34 extinct native mammals vanished under their claws. Conservationists are fighting back; eradication on islands like Dirk Hartog have revived lost species. But across the mainland? The battle’s just beginning. The lesson? Sometimes the smallest introductions leave the biggest scars.