It's actually an interesting aspect of experiencing male gorillas as their odour is used for communicating. I'm sure Pertinax could elaborateIf you want to smell something really bad at Paignton, stand near a defecating rhino or behind the baboon house while it's being cleaned, imho!
Its strongest when they are interacting or otherwise excited. At Paignton the fact its males only plus the warm interior house means its probably stronger/more noticeable than at other places. If you see a male displaying or a gorilla fight you will often get sudden wafts of it in the air. Of course I like it as its synonymous with Gorillas.