During the scene where the 4 chimpanzees are moved to a barn as a temporary home, there is one particular part where two are in the hay loft, one swinging there on a pulley and one having climbed up previously. Hank then tells the others to go into the loft, and three chimpanzees climb the ladder.
Both the film and the book on which it was based make the factual error of calling chimpanzees "monkeys" when they are actually apes.
Although the DVD lists the running time as 89 minutes, the actual running time is 101 minutes.