I do a variety of things. Kiddie pool like Anna's, Ice cubes and cool treats and regular squirts on their underside with ice cold water if we are indoors. Of course I also keep them in the AC if it gets too warm out. Dixie doesn't mind the heat but Dusty hates to be hot. Even in winter he searches for cold spots. I want to get him one of those cooling mats but haven't gotten around to it yet.