Many people let their cats roam freely outdoors. While this may be great for the cats if not a bit dangerous due to cars, malicious humans, and other animals, the big problem with feral cats and foxes is that they are good hunters. Because Australia has such an isolated ecosystem, it’s far too easy for one species to wipe out another one.

A study published by the Proceedings of the National Academy of Sciences on Monday shows that more than 10 percent of the land mammal species endemic to Australia have been wiped out due to cats and foxes brought to the continent by early¬†settlers. If you value the lives of animals, keep your cat inside so it can’t kill animals outside.

To read more about how feral cats and foxes are killing Australian wildlife, click here.