The Knaf Renanim says that the cat is not a predator by nature. It is quite domesticated. The one thing the cat can't stand is a mouse. This intense hatred towards a specific animal is unique to the cat among the animals. The mouse he says, although it seems like it only causes damage, that is only when it comes above ground to steal some food. However in its natural habitat below the ground, the mouse serves an important function in the world, even though we don't know what that function is. Hashem created the cat's ingrained hatred to keep the mouse where it belongs.
The Knaf Renanim says the Nimshal is Torah. The cat is the Yetzer Hara, the mouse is Am Yisroel and the ground is where the Torah is. I once heard a similar explanation with the Nimshal being the Galus. In Galus, Bnei Yisroel has been thrown to the ground. We are to remain there, absorbed only in Torah and Mitzvos. The big world out there with all its attractions is not for us. We are not invited to the party right now. If we stay underground and out of sight, we will remain safe and protected. When we become "curious" and venture out to enjoy the Gashmiyus the world has to offer, the cat or the "Umos HaOlam" become unhappy that we infringing on their turf. They are Hashem's messengers to send us scampering back to where we belong.
Sometimes we venture out too far. The cat sees us and we run but we can't make it back to our hole and we are caught. The cat mercilessly persecutes us and kills us with no chance of escape. The Knaf Renanim says that cat catches his prey batters it and then lets it go. The mouse thinks he has broken loose, but this is just a game. After a few feet he grabs him again and pummels him once more. After a few rounds of this game he finally eats him (I saw this with my own eyes once).
The cat says to the mouse, "Im Tagbia KaNesher V'Im Bein Kochavim Sim Kinecha M'Sham Oiridcha N'um Hashem", if you choose to rise up to places you don't belong, I will bring you down. "Erdof Oivai VaAsigaim V'Lo Ashuv Ad Kaloisum" I will chase my enemy and not return until I wipe him out.
When caught the mouse says, "V'Ata Tzadik Al Kol Haba Aleinu Ki Emes Asisa V'Anachnu Hirshanu"; you are justified in all you do. You are correct and we have been wicked.
It's been a long galus with us buried in the ground. The times we've come up we've been hunted and killed. Hang in there and don't leave your place. Our time will soon come and HaKadosh Boruch Hu will say, "Hisnari MeiAfar Kumi"; brush off the earth and rise once again. Bimheira Biyameinu Amein!