This is a white-faced Capuchin monkey family. They are not shy. On wildlife-viewing boat trips on the Tempisque River in Palo Verde National Park, they will actually hop on the boat and take pieces of banana out of your hand, if you offer food to them. Each time I have taken that trip, we have encountered a group of at least 10 monkeys, including several babies riding on their mother's back, as you see here. They live in groups of between 6 and 40 monkeys.
They are native only to the western hemisphere, from Central America ranging as far south as northern Argentina. Early Spanish settlers named them after the Capuchin monks of the Franciscan order because the resembled the dark robes, with only white faces exposed, of the monks.
My wife is not a fan of white-faced Capuchin monkeys, as she thinks their faces are too expressive and, at times, human-like. Visitors on the wildlife-viewing boats, especially children, delight in the contact with the monkeys. It is certainly much more thrilling to see monkeys in the wild than in a zoo, and Costa Rica is a place where one can be virtually guaranteed of seeing monkeys in the wild if visitors go to the right places. They are territorial, so the wildlife tour operators know right where to go to find them.
White-faced Capuchin monkeys are considered the most intelligent of the western hemisphere monkeys. In the wild they use tools, such as stones, to crack open nuts. They are easily trained and they were the species used by organ grinders. In modern experiments, some white-faced Capuchins raised by humans as infants have been trained to be assistants to quadriplegics and have been trained to do tasks such as opening bottles and even micro-waving food.
White-faced Capuchins, also called white-throated Capuchins, are about 46 cm (18 in.) in length, plus a tail as long as their body. The Spanish word for monkey is mono, and they are called mono carablancas. Their scientific name is cebus capucinus.