Belonging to the primate order, it is a mammal closely related to humans. Medium in size, with equal limbs or slightly longer hind limbs, varying tail lengths, cheek pouches and arm calluses, suitable for arboreal or terrestrial life. The skull is larger and the cranial cavity is spherical, which is due to the shortening of the jaw and flattening of the face. Smell is usually secondary to vision and touch, and certain species have highly developed olfactory centers in the brain. The social behavior of monkeys is complex, usually living in groups and forming a hierarchical social structure. There is a variety of food, including fruits, leaves, insects, small animals, etc. In culture, monkeys are often seen as symbols of wit and flexibility.