Due to being geologically isolated for millions of years before white settlers showed up, Australia developed thousands of unique animal species with their own prey and predators. Then Europeans showed up with their own animals and threw everything out of balance. Rabbits almost denuded the continent before a humans decimated the horde with germ warfare. Feral cats are eating up the native bandicoots and growing to the size of American wolverines. Sparrows are crowding out native parrots. In a small island off the coast of Victoria which recently became accessible by land, foxes have been massacring the little penguins that used to call this place home.
Flightless birds are no match for these imported predators. But just before they were made extinct, a local farmer talked the government into allowing him to import a certain protective sheepdog that had been bred to protect livestock. He placed these Maremmas around the island and the penguin population climbed from less than 10 to more than 150 today.
A cute story like this has attracted the usual Hollywood lies so you can find an exaggerated version of the story in the movie