Catz features two mice, one white and one gray. The Mice are constructed similarly to petz, of ballz and linez. The Mice are exclusive to catz and the full version of petz. It is possible to hex mice, but it is not commonly done.
The player can interact with mice in a variety of ways. Players can pick up mice with the mouse. Mice are held very similarly to the way petz are, with the exception that they appear to be held by their tail, not neck, and may be picked up using the left mouse button. A mouse may also be lured out of its hole by use of toyz. Mice will leave their mousehole to examine toyz left on the ground. Some items, such as the cheese toy, can act as food for the mice. Picking up toyz and the mice themselves may spook or startle them, and they will run back into the mousehole. Petz can also interact with the mice. Petz can pounce and pick up mice. Some petz are better at catching mice than others, such as the B+W Shorthair. Usually, after a pet interacts with a
mouse, it will startle and run. In rare instances some players have recorded that their catz have eaten the mice. Mice do not have neglect levels or needs like petz, and simply act as a 'minor character' in the Petz Series. Mouseholes have the option to be closed by going to Options -> General Options and clicking the box 'mouse holes closed' if players do not want the mice to run around.