Basic Tips:
Primates are scared of water, so the moat should be a knee deep wet moat.
Give lot of enrichment activities such log platforms, tyres rope swings etc for them to play.
GIve them open shelter areas to take shelter during rains.
Since primates stay in groups, there is always a dominant male who would be in Charge of the team and the female primates. The other male primates can often come into a fight
Landscaping should avoid itching plants, shrubs and trees. .
Do let me know, if you should need more specific design. Would be happy to see your design once completed.
