I was lucky enough to encounter many Capuchin monkeys in Costa Rica. After watching them for some time, I was able to observe some of their relationships and behaviors. In the first image, I had clearly met one of the more senior and respected members of the group. This individual was happiest observing the humans that were observing him, and was quite content in sitting back and allowing the other younger capuchins to cause a raucous.
They often moved together as large family groups, and when they did it was like a tornado moving through the trees. At one point they needed to cross a road, and before letting the mums and bubs exit the safety of the trees, they sent out scouts (pictured in the second image) to make sure the coast was clear. Once the scouts gave the all clear, monkey after monkey came flying out of the trees to scurry across the road and back into the jungle. Some of their leaps from tree to tree were incredibly far and seemed very dangerous, but they were completely confident and surefooted.
The monkey pictured in this last photo was caught making quite a mess with the little fruits hanging from this palm tree. Surely a source of food for these cuties, but at times it looked like it was having more fun throwing the fruits to the ground than actually caring to eat them. I think their cute little faces easily fool humans into thinking they are very friendly, but in contrary they can be quite aggressive and territorial and wont hesitate to flash some pretty sharp canines if you get too close.