According to Serkis, who is currently shooting Peter Jackson's The Hobbit, those wearing motion capture suits were treated differently from everyone else!
“In the Planet of the Apes documentary they talked about how the orangutans hung out with the other orangutans, the chimps hung out with the chimps, and the gorillas hung out with the gorillas," Serkis tells Showbiz Spy. "And to a certain extent there was a little bit of that shooting this movie. We tended to knock around together.”
What he's referring to is the late Charlton Heston's oft-told story of the way that actors dressed as chimps, gorillas and orangutans tended to center around each other, creating a sense of segregation on the set of the original Planet of the Apes.