Six months later, during adolescence, the bridge of the monkey's nose gradually becomes taller and the distance between the mouth and nose gradually widens, making the monkey's face look more three-dimensional. In addition, the hair begins to become thicker and the color gradually deepens, showing a mature temperament.

When Shisong monkeys enter adulthood, their monkey faces have basically been finalized. The face of an adult Shisong monkey displays a deep, wise look. His eyes are still bright, but they are more calm. The bridge of the nose is high and the distance between the mouth and nose is moderate, making the monkey face look more coordinated. In addition, the hair of adult squirrel monkeys is thicker and darker, demonstrating their leadership temperament.