This fence has appeared since my last visit 3 years ago. I didn't ask about it but guess it's dual-purpose - to stop children being placed on the wall and to give the gorillas the illusion of privacy.
The keeper explained that 4 year old Indigo is undergoing the transistion from indulged baby to 'real' gorilla and is being taught how to shoulder charge, for instance, and also not to stare. The keeper asked us to be careful about staring at Badongo for too long as he sees it as a challenge and will react in some way eg by throwing things.
