This really interesting thing happened while we were at the menagerie. A young orangatan was pushing a big piece of fabric out of his/her enclosure. An older orangatan watched, unconcerned. It pushed with it's fingers through the holes of the fence. It had one part out and tried to push another part through another hole, finally figuring out what to do, pushing and pushing, it got the entire piece out and it landed on the ground at our feet practically. A crowd had gathered. Some of us were cheering him, some saying "No, don't do it!" When he was successful, we all clapped. Then he/she went and got two rope toys and tried to push them out, too. There were no staff people around. When we left, the oran' was till working on cleaning house.