Old World monkeys are a group of primates found primarily in Africa and Asia. They belong to the family Cercopithecidae and are characterized by their narrow nostrils, which face downward. These monkeys typically have non-prehensile tails, meaning they do not use them for grasping. They are known for their diverse diets, which can include fruits, leaves, and insects. These monkeys are social animals, often living in large troops. They exhibit complex behaviors and communication methods, making them fascinating subjects for study. Some well-known species include the baboons, macaques, and colobus monkeys.