Why would God make sentient prey animals?

It seems like a good ecological structure to have certain animals that eat plants and other animals that eat meat and it all fits together to keep the ecosystem going smoothly. But isn't it a little strange to think that a good, loving, wise god would create a world full of sentient, thinking, feeling creatures that feel fear and pain and that have a will to live, but whose purpose in life is to be hunted and brutally killed by other animals? Think of all those poor rabbits out there in the wild. Why didn't God just create a world where all animals eat plants? To keep animal populations under control, just have it be that animals reproduce at much lower rate.