a toilet seat device and associated training method for pet animals that permit dual purpose use of a household toilet by both humans and pets , the toilet seat device comprising a toilet seat supported by a commode and having a plurality of shelf segments . the shelf segments are extendible to a protracted position to reduce the size of the central aperture of the toilet seat by a handle member operably connected to a cable and roller assembly which interconnects the shelf segments , and are automatically retractable in response to the weight of a human occupant on the toilet seat , or by manual manipulation of the handle member .