With its complex communication system, the white-faced capuchin monkey (Cebus capucinus), which lives in the lush jungles of Central and South America, fascinates scientists alike. These small monkeys, which may be identified by their distinctive brown or black fur and "white face" mask, use a variety of noises for social interaction, communication, and environmental navigation.

The animal kingdom is filled with fascinating creatures, each with its own adaptations and characteristics. Among them, the spider monkey stands out as a treetop acrobat, known for its long limbs and a distinctive feature: it has four fingers. But why do spider monkeys only have four fingers when most other primates have five? In this article, we will delve into the world of spider monkeys to discover the reasons for their unique adaptations.