"Pony is an orangutan from a prostitute village in Borneo. We found her chained to a wall, lying on a mattress. She had been shaved all over her body. If a man walked near her, she would turn herself around, present herself, and start gyrating and going through the motions. She was being used as a sex slave. She was probably about six or seven years old when we [the Borneo Orangutan Survival Foundation] rescued her, but she had been held captive by a madam for a long time. The madam refused to give up the animal because everyone loved Pony and she was a big part of their income."
-from
here.
Added at 8:02: I just found a video about orangutans in Borneo and the BOS Foundation's work, and there's a part about Pony twelve minutes and forty five seconds into it:
http://youtube.com/watch?v=Qv8NlidN2wg. It's not graphic, but it's pretty horrible.