Capuchins live in troops of 10 to 20 monkeys, all related. They look after each other's babies, share food, and warn the troop when danger is near. A young capuchin will spend several years watching the older monkeys to learn what to eat, how to find water, and how to crack open hard food.
They are one of the smartest monkeys in the Americas. Capuchins use tools - they pick up stones to crack open nuts, and they rub a stinky plant or insect on their fur to keep biting bugs away. Scientists have watched them teaching their babies how to do this.
Their long tail works like a fifth arm. It can curl around branches and hold the monkey's whole weight. That means a capuchin can hang upside down and use both hands to grab fruit at the same time. Very handy if your meal is wobbly.
Capuchins also have a sweet tooth - or rather, a fruit tooth. They love bananas, mangoes and figs. In some parts of Costa Rica, they have learned that tourists carry snacks, and they will boldly sneak in to investigate a backpack. Visitors are asked not to feed them, so they stay wild and healthy.