Cat pooping on shag carpet.

Question
My fiance and I just adopted a cat. She uses the litter box every time she need the bathroom. However, we have a shag throw rug in the living room. Turns out my fiance had animals before and the loved go to the bathroom on that carpet. My question is: Why do the animals like to go to the bathroom on the shag carpet?

Answer
Well that's hard to say, especially since those animals are no longer there.

If your cat is using the rug it's because others have left their markers on it and now she wants to cover over the smell they left behind.

Also them using the rug signals to her that it is 'okay' to use it as a potty.

I would toss it out or bleach it if I were you.
Otherwise your cat will also potty on it.