Yes, after the first year there were some gnaw marks on the floor and
walls - grams was insistent that it was done by rats and not by her.

So we told her that if she was so sure there were rats in my house,
that she should hunt them down to live on. And she did; for 3 weeks we
gave her no food or water and she made it through just fine. And now I
don't have a rat problem anymore.