Firstly, I was amazed when I looked across and saw the De Brazza's Monkey on the island, and then when Namoki approached it and they started to play tag, I was open-mouthed They both seemed to enjoy the game. Jock was sat below the climbing frame watching them and at one point, he got up and threw a clump of grass at the De Brazza!! I don't know if he was defending his daughter, or just annoyed that the monkey was on his island, but he sat back down and continued to watch them for a while before heading indoors.
This was the only De Brazza on the island, but I believe there was at least one more inside.
it doesn't always work out so well longterm... Silverback Motaba at Melbourne killed one of the DB's in their mixed exhibit. jomie killed a Colobus at port Lympne.
AFAIK there are still 3. The other two are mother & daughter. This is a new male who replaced the previous one that died. He seems to be very adventurous but I believe he is not full integrated with the females yet.