But then, someone let the cats out. Literally. Domestic cats became feral. And, since they're about the same size as quolls and enjoy a roughly similar taste for wild Australian cuisine, cats quickly became their most cutthroat competitor.
"Feral cats are one of the most efficient hunters and can be devastating to wild populations of mammals and birds. Their retractable claws allow them to climb swiftly - even upside-down. Because of this they are unlike any other predator in Tasmania and can take tree dwelling animals, birds and eggs with relative ease. This, together with their size and stealth, makes them well suited to taking prey that quolls eat."
In a nutshell? Cats are very, very good at life.
We love cats. But keeping them unspayed and outdoors for a century or two will have consequences.