Peanut Butter has figured out that if he squeals he will get my attention. So I get squealed at when he's had enough of floor time, when there's poops in his food bowl, when he's nudged his pigloo over the his food bowl blocking access to it, when the hay needs topping up, when it's time for vegies (according to him) and when the little towel they like to sprawl on needs to be changed because it's been peed on too much and/or has too many poops to be layed on. Also, when I remove the dry food bowls for cleanout, he squeals in protest until new bowls appear.