Vocal Communication in Woolly Monkeys (Lagothrixlagothricha lugens) in Cueva de los Guacharos National Park, Colombia

Vocal communication represents several advantages for primates. Numerous studies have shown that there are different factors that affect vocal behavior. Here, we combined classic and bioacoustics methods to provide the first comprehensive analysis of the acoustic structure and the vocal behavior of a wild population of woolly monkeys (Lagothrix lagothricha lugens). This species is of special interest because it is one of the few neotropical primates whose vocal communication is still not understood completely. Results indicated that factors, such as the time of the day, activity, age, and sex, had major influences on the vocal behavior of the woolly monkey. We also show evidence of how call rates changed, between highland and lowland woolly monkey populations, due to intrinsic differences of each location. Acoustic structure analyses of two types of vocalizations show consistent acoustic differences among the calls of individuals in some features (i.e., call duration and high, low, and final frequency). These differences may enable woolly monkeys to distinguish between the calls of different group members. Finally, clear differences between age (juvenile vs. adult) and sex (male vs. female) classes were found, based on the structure of the alarm call.