During our visit, we learned that there are four different cats, all identical-looking tabby cats, who play this one fuzzy character. Their names are Gonzo, Rizzo, Reggie, and Archie. They all serve different purposes: one is for looks (the handsomest!), one is for "paw batting," one is for running, and if memory serves me correctly, one is good at rubbing up against legs.
There are two cat wranglers on set: a man and a woman named Mark Harden and Ursula Brauner, part of Animals For Hollywood. They're delightful, for the record.