The nest box should be 1 cubic foot – 1 foot by 1 foot by 1 foot, made from 1 inch thick plywood screwed together with stainless steel screws, and painted with non-toxic paint. A 4 inch diameter circle hole for the entrance should be drilled on one of the sides of the boxes. Inside the box goes 3 or 4 dish towels which need to be changed every 4 months. The box should be on the outside of the cage so that the only thing exposed to the monkey is the entrance hole of the nest box. The rest of the box should be protected by the wire so the monkeys do not chew on the nest box wood from the outside.