Trivia: In an homage to Twlight Zone episode with William Shatner watching the monster rip up the airplane wing, Ben Stiller as Alex the lion watched the monster/tarsier tear up the wing of the airplane too.
Trivia: Bernie Mac died before the film was released to the general public, the film was released posthumously in 2008 with a tribute message to Bernie in the end credits.
Chosen answer: There's two reasons. Firstly, infants are only allowed to work for short periods of time, hence why when you see babies onscreen that are heavily featured, invariably twins are used to alternate to not fall foul of the rules. Secondly, it may be that one of the voices didn't give the filmakers as much diverse dialogue as they needed so they brought in another actor to get the rest they needed.
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