These are a matched set in actuality. Both were present on the extraterrestrial worlds and the reason was they were a counterbalance to one another. This is an illustration of how the divine realm works to not decimate and destroy but to counterbalance with opposing forces as requested by the Law of Karma to render a payback of some kind. But the intention is not to make the intelligent life forms who are troublemakers suffer extinction, so there will typically be introduction of life forms that will provide a partial solution to keep things in a kind of balance ultimately and prevent devastation.
This is not to say that circumstances might get out of control for a time and cause severe problems, but that will be governed by the Law of Karma to happen if it does, and in those instances is warranted from the perspective of the karmic forces that are working to bring misfortune to perpetrators as a payback for their wrongdoing. But the cat and mouse are a matched set—one is a pest, the other a predator. It is important to understand as well that cats were repurposed to be a human companion animal and, in this way, is less of a scourge to humanity because it does not see people as its enemy. That is not the case with cats in the extraterrestrial worlds, they are truly feral beasts and a danger to anyone approaching them. They are more akin to the cougar and other small wild felines you know of that are similarly extraterrestrial predator species introduced here to add to human difficulty.