Get over here: black capuchin monkeys use long-range vocalizations to adjust the distance between individuals.

Abstract

When dispersed, some primates' species can use long-range vocalizations to exchange information about spatial position within the group and to coordinate behaviors, and it is also believed that these vocalizations play a role in communication between groups. These vocalizations help adjust the distance between individuals and are individually recognized. Thus, our objective was to analyze whether the distance between individuals within the group changes after a long-range vocalization. The target of the study was the population of black capuchin monkeys (Sapajus nigritus cucullatus) inhabiting an area within the southeastern Brazilian Atlantic Forest, the Carlos Botelho State Park. We measured group spread: the distance between the coordinates of the location of the tree most distant group members at every 5 min during entire days. Long-range vocalizations were recorded as all occurrences. The transfer function, analysis derived from time series, indicated that the distance between individuals decreased in the first scan after each long-range vocalization. We conclude that long-range vocalizations can be considered as one of the mechanisms responsible for maintaining distance between individuals of the same group.