RESUMEN
Cebus are a very cognitive species. They have expansive motor abilities, demonstrate a high levelof proficiency in using tools to obtain food; and play, using thoracic members. Our objective in thiswork is to study the shoulder and arm muscles of Cebus genus, comparing the findings with theliterature data on humans, chimpanzees and baboons, and assume these aspects are associated withbehavioral characteristics. We conclude that the shoulder and arm muscles of Cebus, in generalterms, are more similar to baboons, perhaps due to the quadruped behavior exhibited in these animals.The conventional term hand abilities in primates, specifically in Cebus, originate in motorabilities, generally, from thoracic members. They are controlled by a high encephalic index, and notby specific motor abilities from the intrinsic muscles of the hand and forearm which act on the hand.