SHORT-DISTANCE VOCALIZATIONS OF THE BLACK-AND-GOLD HOWLER MONKEY (ALOUATTA CARAYA) IN THE ATLANTIC FOREST OF ARGENTINA

DI BITETTI M. S.; HOLZMANN I.; AGOSTINI I.

Primatology in Argentina

Sociedad Argentina para el Estudio de los Mamiferos

Año: 2017; p. 201 - 215

The vocal behavior of howler monkeys (Alouatta spp.) includes long and short-distance vocalizations, the latter of which have seldom been studied. Naturally emitted short distance vocalizations (used in intra-group communication) of two groups (26 individuals) of black-and-gold howler monkeys (Alouatta caraya) in the Atlantic Forest of Argentina, were recorded during a period of six months (June 2007-November 2007). For each sound-recording, sex and age of the sender and behavioral context (feeding, playing, aggression between group members, isolation, tense moments and infant distress situations) were noted. Four spectrogram measurements (minimum, maximum and peak frequency and duration) were taken in 331 calls using the software Raven 1.4 (Cornell University). We recognized (by sound and form) eight different types of short-distance calls: Hu-hu-hu, Heh, Bark, Moo, Ar, Yell, Screech and Oodle. Although we did not test functionality, the consistency of some of the contexts in which the signals were recorded show that some of these vocalizations can function to reestablish contact between lost individuals (Moo call), as a warning of a close danger (Bark), or during aggressive interactions between group members (Screech). This descriptive study sets the stage for future ones designed to test hypotheses about the proximate mechanisms and function of each call to further our knowledge of intra-group communication in howler monkeys.