Why does a cat think she's a dog and how would you know?

[rz]

We had one cat who learned to play fetch at the age of 10. He would drop his toy at our feet and look up at us and meow. We'd throw it down the hall, and he'd bring it right back.

We're trying to teach one of our newer cats how to fetch. She has brought a toy back a few times, but it still hasn't sunk in yet that she needs to bring it back to us if she wants us to throw it again.