In this photo he is looking at one of the den doors, you can see it is set as a 'creep' so he can't get in but the younger ones can slip in and out if they need to get out of the way. Actually he is a pretty gentle male but he does discipline them I think.
The two youngsters that I have taken the photos of were going in and out of the den all the time (especially when Pertinax first climbed down onto the floor). He was obviously interested in what was going on in there
These youngsters haven't been in with him very long so there's probably still some interest on his part and nervousness on theirs...
Pertinax has a favourite sleeping platform on the top level(I think it was installed specially in his favourite spot) It is very much 'his' and I've never seen any others use it. One day he 'appeared' to be asleep on it with a little store of food he had collected nearby. One of the (previous) youngsters, probably Mapema or Damisi, went over and tried to grab some- Pertinax was off his bench in a flash and the youngster fled...