In 1788, British settlers brought domestic cats to Australia as part of the First Fleet, intending to use them to control rodent populations on ships and farms. Genetic studies and historical records show that these cats rapidly spread across nearly the entire continent within 70 years, adapting to almost every habitat—from the mountainous regions of southeastern Australia to the dry central deserts. Scientists recently re-examined historical data and found a consistent pattern: the last recorded sighting of an indigenous mammal that is now extinct in a particular area always occurred after the arrival of cats. This correlation suggests a significant impact of feral cats on native wildlife. Indigenous animals such as marsupials, ground-nesting birds, and reptiles have been especially vulnerable to the presence of feral cats. Iconic species like the numbat and the nocturnal parrot have shown particular sensitivity to these invasive predators. In contrast, rodents introduced by humans, such as house mice and warehouse rats, have thrived because they evolved alongside humans and can adapt to human-modified environments. Native Australian animals, however, had no prior experience with placental carnivores like cats and foxes, having only recently encountered the dingo about 4,000 years ago. Australia already had its own small carnivore, the quoll, which shares a similar ecological role with domestic cats. However, feral cats have proven to be more efficient predators, causing harm through direct predation, disease spread, hybridization with native species, and competition for resources. These factors have contributed to the decline of many native animals. Efforts to protect Australia's biodiversity have evolved from trying to completely eliminate feral cats, which is seen as impractical across such a vast area, to more sustainable strategies. These include restoring dense shrub vegetation to provide safe habitats for small marsupials and creating enclosed areas where predators are excluded. Some conservationists also relocate native species to protected refuges. However, these efforts are not always successful, as feral cats can quickly regain dominance in areas where native animals have been reintroduced. Recent studies published in early 2026, using advanced statistical methods, have reaffirmed the strong link between the arrival of cats and the extinction of native mammals, even more than 200 years after the First Fleet landed at Botany Bay. This ongoing research highlights the long-term and significant ecological impact of feral cats in Australia.