Quote from Ross in The One Where the Monkey Gets Away
Ross: You called Animal Control? Rachel: Why? Do you not like them? Ross: Marcel is an illegal exotic animal. I'm not allowed to have him in the city. If they find him, they'll take him away from me. Rachel: Okay, well, now, see, you never ever, ever told us that. Ross: That's right, because I didn't expect you were going to invite them to the apartment.