"She's not trying to break out, that is not her aim, she just messes with various things, including the fence, but also the water pipes and heating, and she causes damage. She uses branches and whatever else she can find as tools," Christine Kurrle, zoo spokeswoman told The Local.
"So far she is the only one of the six who does this kind of thing but it is obviously not in our interest that the others learn how to manipulate the fence."
The 20-year-old orang-utan called Sirih, has become so good at making holes in the fence around her enclosure, and digging up the water and heating pipes that the zoo has stationed a security man to watch over her and raise the alarm at the first sign of trouble.
She may soon be on her way to a new home anyway, said Kurrle. "Sirih is being moved because she is a healthy, strong female and needs to leave the group to be paired with a mate. We don't know when or where yet, that will be determined by the international breeding programme."