Tigger still mouthpants when she has been running around like a wild child. Mouthpanting is their way of keeping cool. Cats only loose heat from their bodies out of their paw pads, so mouthpanting is their only other way to really "cool" down. We have been having a humidity wave over here in the New England states, and I let Tigger and Smokey out to play last weekend, poor Smokey can running back with his mouth open and wanted back in the house.