Originally Posted by big cat

Either put gerbils out of the cat's reach or get rid of the cats or the gerbils. Cats are hunters. Gerbils are prey to cats. You can't punish a cat AFTER anything he has done. Like dogs and other animals, they do not understand past, present and future. They just are, in the now. You can't say to a cat "You ate that gerbil half an hour ago, you're bad, so I'm going to punish you".