Spike Jonze had his voice cast act out their characters on a soundstage, to ensure that the voices came from a performance of actors and actresses working together, instead of filming the movie, and recording the voices later, or recording the cast members individually. The actors and actresses wore radio microphones attached to their heads with headbands. Jonze and Catherine Keener would perform Max. Even before this soundstage shoot, Spike took the voice cast to Griffith Park to wage an actual dirt clod war.
In July 2006, less than six weeks before the start of shooting, the Henson-built monster suits arrived at the Melbourne soundstage where Spike Jonze and his crew had set up their offices. The actors climbed inside and began moving around. Right away, Jonze could see that the heads were absurdly heavy. Only one of the cast members appeared to be able to walk in a straight line. A few of them called out from within their costumes that they felt like they were going to tip over. Jonze and the production crew had no choice, but to tell the Henson people to tear apart the fifty-pound heads, and remove the remote-controlled mechanical eyeballs. This meant that all the facial expressions would have to be generated in post-production, using computers.
Initially, Warner Brothers was so unhappy with Spike Jonze's final movie (it was much less family friendly than they imagined) that they wanted to re-shoot the whole seventy-five milion dollar project in early 2008. Jonze was eventually given some more time and money by the studio, in order to make the final product satisfying to both the studio and him.
Spike Jonze turned down the chance to make the movie fully animated, because he wanted people to feel the Wild Things, and thought it would be more exciting and dangerous, if a real kid were running around with the wild things.
Though their names are not mentioned in the book, Maurice Sendak named the Wild Things after his aunts and uncles: Bernard, Tzippeh, Aaron, Moishe, et cetera. In the film, they have totally different names.
The movie's release generated conflicting views over whether it is harmful to expose children to frightening scenes. Spike Jonze indicated that his goal was "to make a movie about childhood" rather than to create a children's movie. Dan Fellman, Warner Brothers' head of movie distribution, noted that the film's promotion was not directed towards children, advising parents to exercise their own discretion. In an interview with Newsweek, Maurice Sendak stated that parents who deemed the film's content to be too disturbing for children should "go to hell. That's a question I will not tolerate" and he further noted "I saw the most horrendous movies that were unfit for a child's eyes. So what? I managed to survive."
The creatures are being portrayed by actors in six to eight foot tall costumes, with some additional animatronics, and computer-generated faces. The costumes were created by The Jim Henson Company, who were responsible for the Muppets, and the Labyrinth (1986) creatures.
Numerous cameras followed the actors and actresses around, to impress their expressions and feelings. The images would then be digitally "infused" onto the faces of the puppets, and would follow the cast members' performances.
It has been said that actors and actresses in the monster costumes would wear the head for no more than half an hour at a time, after which, they would have ten to fifteen minute breaks in front of an air conditioner. Stunt performers would remain fully suited for several hours at a time, without air conditioning.
When Max's mother is shown speaking on the phone to her co-worker, she asks why "Mr. Lasseter" (presumably her boss) didn't like her report. This is most likely a reference to John Lasseter, who was one of the original artists on the now famous "Where the Wild Things Are" Disney animation test.
An early test scene made by Disney back when the movie was expected to be done through traditional hand-drawn animation, featured Max writing his name on the wall of his room with a marker and chasing his dog down the stairs. The opening scene of this film is similar to this, as it features Max chasing and wrestling with his dog. Though ultimately, the scene is an homage to the second picture in the book, featuring Max in his wolf suit, chasing his dog down the stairs with a fork in his hand. Disney's scene can now be found on YouTube.
Spike Jonze was approached by Maurice Sendak, and was asked to take on the film adaptation. A movie had been on the burner since the early 90s, and Mr. Sendak had not been able to find anyone fitting to take it on.
Maurice Sendak personally favoured Spike Jonze as director, noting he was "young, interesting and had a spark that none of the others had". Jonze kept in close consultation with Sendak throughout the process, and the author approved creature designs created by Jim Henson's Creature Shop.
The costumes for the wild things arrived and were heavy, bulky, and awkward for the cast members wearing them. The faces were entirely blank, leaving freedom for CGI faces to be added later, but proved to be a challenge for Max Records to work around, as he was basically talking to a faceless object, with an actor or actress uttering the lines behind him.
Michelle Williams was, at one point, cast to voice K.W., but the role went to Lauren Ambrose. The reason given by the filmmakers for this, was that Williams' voice didn't match what they were going for. Chloë Sevigny was another consideration for the same role.
Getting the scene where Max runs and barks at the dog proved to be quite difficult, as getting him and the dog to move in rhythm proved to be much more of a challenge. Jonze had to resort to shooting the two separately.
In the 1980s, the first serious production was started, backed by Disney. It would have blended traditionally animated characters with computer-generated settings. While an animation test was completed as well as a few other story elements, John Lasseter was ordered to halt production (it didn't help that the combination of traditional animation and CGI annoyed some traditionalists in upper management), and the film proceeded no further with the company.
Sam Longley, the suit performer for Ira, is a Perth Western Australia actor famed for his comic and improvisational performance skills. He is also six foot ten inches tall, and brother of Luc Longley of Chicago Bulls fame.
Rumors of Arcade Fire doing the soundtrack spurred much fanfare for fans of the band. It has never been confirmed, but the band apparently worked on a partial score, and then decided to abandon it. Karen O from Yeah Yeah Yeahs was called in to record the soundtrack instead, which was allegedly rushed.