Though many people consider sloths silent creatures, these animals interact—especially during significant events like mother-infant bonding. Particularly, young sloths are surprisingly noisy; they squeal high-pitched when separated from their mothers. As a distress call, this sound guides mother sloths toward their offspring so they might help in their reunion. The vocalization is quite important in dense jungle surroundings, where vision is limited, and sounds transfer better than sight.

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.