Abstract: A diaper is provided for a domesticated animal and includes a first portion and a second portion, each sized based on a circumference of a waist of the animal. The diaper includes a third portion to link the first portion and the second portion, and is sized based on a second distance from a location on a back of the animal within the circumference to a location on an underside of the animal within the circumference of the waist. The diaper further includes a hole formed within the third portion to pass the tail of the animal. A first edge of the tail opening is positioned based on a first distance from the back location to the first edge of the tail, and a second edge of the tail opening is positioned based on a mid-point of the second distance.