According to Futility Closet (attributed to Planet of the Apes Revisited, 2001):
During the filming of Planet of the Apes in 1967, Charlton Heston noted “an instinctive segregation on the set. Not only would the apes eat together, but the chimpanzees ate with the chimpanzees, the gorillas ate with the gorillas, the orangutans ate with the orangutans, and the humans would eat off by themselves. It was quite spooky.”
James Franciscus noticed the same thing filming Beneath the Planet of the Apes in 1969. “During lunch I looked up and realized, ‘My God, here is the universe,’ because at one table were all the orangutans eating, at another table were the apes, and at another table were the humans. The orangutan characters would not eat or mix with the ape characters, and the humans wouldn’t sit down and eat with any one of them.
Is the above story true or fiction?