Some researchers --noting their reflective intelligence in lab studies comparable to, maybe exceeding in some situations, that of chimps -- wonder why such intelligence evolved in these creatures. Foraging, perhaps? Social interactions? One orang, Chantek, has supposedly been taught some 100+ gestures or signs-- about the same as a 1-2 year old child picks up on her own.
Recently Galdikas has taken some criticism for her failure to maintain the mandated care of orangs in her facility. I don't know if this is a political matter or an actual reflection of conditions in Indonesia which are not that good even for the humans! (She is aware, unlike some others, of how important the early experiences of an orangutan or any primate are. See Harlow's work, for example. .. . treating orang infants like human infants may keep them alive but it may transform them into chimeric creatures neither human or orang...)