Casting and filming
Mouse Hunt would be shot between March 3 and July 3, 1997, in various locations across California. It was shot around the same time as Amistad, which Spielberg directed on the east coast of the United States. Verbinski played a role in selecting cast members for Mouse Hunt. One of the film's actors, William Hickey, died on June 29, 1997, just days before shooting wrapped.
The outdoor scenes have depictions of snow and the majority of them were shot in Central and Northern California, particularly around Fresno and the Yosemite region. Wilshire Boulevard in Beverly Hills was used for exterior shots representing the upscale restaurant. Additionally, Raleigh Studios in Hollywood was where many of the mansion's interior shots were constructed and filmed. In a 1997 interview, Verbinski said that the flood scene towards the end of the film was a collaborative effort between special effects leader Michael Lantieri and the film's stunt team. In this same interview, Verbinski reflected on the shooting, saying that "we weren't anywhere near anything sane during the entire shooting of the movie. Especially with Nathan and Lee, they sort of promote insanity."
Verbinski sought real mice for the film since this realism contrasted with the absurd nature of the film's two leads. The casting process for the mice was detailed in a December 1997 news article titled "Mouse Hunt: Hollywood's hunt for the perfect set of... ears". Regarding the ideal type of mouse he wanted, Verbinski said in this article "I did not want a cigar-smoking, bow-tied mouse. I wanted a really harmless kind of mouse. A lot of mice are too beady-eyed, too ratlike." Verbinski eventually turned to professional animal trainer Boone Narr to find the right mouse for the film. Narr presented various mice based on color and size specifications, and Verbinski selected two that closely matched his vision — though he requested a lighter underbelly to better evoke the image of a "church mouse" with expressive charm. According to Narr, Verbinski sought a mouse that could not only perform but also connect emotionally with audiences. To fulfill this unique casting challenge, Narr turned to online outreach, posting a call for mice fitting Verbinski's precise criteria. The search yielded an overwhelming response — with over 8,000 submissions, which Narr jokingly referred to as 'rodent head shots'.
Of the initial group of mice evaluated, four met the casting requirements, far fewer than needed for the production. To realistically film Mouse Hunt, Verbinski required a total of 60 mice: one principal mouse for close-ups and nuanced scenes, and 59 to perform various stunt and action sequences. Narr addressed this challenge by breeding the two mice initially selected by Verbinski, ultimately creating a colony of sixty. From this group, one standout mouse was chosen for leading scenes. Meanwhile, the rest underwent specialized training, organized into teams based on their abilities — including running, climbing, and jumping — to fulfill their respective roles during filming. Narr taught them intricate stunts, including curling up in a sardine can bed. A CGI mouse by Rhythm & Hues Studios was used sparingly, mostly for stunts too complex or dangerous for real animals. An animatronic robot mouse built by Stan Winston Studio was also used for some close-ups and expressive moments. It had remote-controlled facial features and internal bladders to simulate breathing. Scenes involving the vicious cat named "Catzilla" were done using a similarly realistic Animatronic robot cat.
Verbinski described the most difficult aspect of the film's production as being the logistics of filming the mice. It required a second unit running simultaneously to the work with the human actors. During early tests with the live mice, there was an entire day of shooting where the crew wasn't able to get a single usable shot. These early tests concerned the crew and made them realize how much time they would need to spend on the mouse scenes. While shooting, they sometimes would need up to 130 takes to get the mice to do what they were required to do. This number is only 18 takes less than the official record listed in The Guinness Book of World Records, which was for a scene in the 1980 film The Shining. Verbinski said in 1997 "unlike with the actors, who I encourage improvisation, the mouse, if he improvises, that means he walks out of the shot. That was kind of crazy to sort of [say to the mouse] 'No it has to be like this', and then come over and [say to the actors] 'that was interesting'. This was organic and [the other] was surgical and very strict."
