Researchers hypothesize that male loud calls play several roles in primate societies including in the context of intergroup spacing and spatial coordination. Field studies examining the behavioural correlates of vocalizations are essential to evaluate the function of these calls. This preliminary study, from July 2011 to January 2012, explores the behavioural contexts and correlates of male loud calls in a habituated group of red langurs (Presbytis rubicunda) in the Wehea Forest, East Kalimantan, Indonesia. In analysing 418 h of data collection, we find a total of 87 vocal behaviours, including bouts of multiple calls in rapid succession (i.e. calling events) and individual loud calls. In this sample, most vocal behaviour takes place in the morning with 59% of calling events occurring before 8.00 h. The mean rate of calling events is 0.12 events/h, and the mean rate of individual loud calls is 0.20 calls/h. The mean number of calling events per day is 1.31 (range: 0-4), and the mean number of individual loud calls per day is 2.81 (range: 0-13). The rate of calling events is highest in the context of intragroup conflict, followed by intergroup encounters, predator threat, group travel, and the highest number of individual loud calls occurred during intergroup encounters. Although these results are preliminary, they suggest that adult male loud calls among red langurs at Wehea may play a role in both intergroup spacing and social coordination, supporting the hypothesis that these calls can serve different functions.

Keywords:
Intergroup spacing, Spatial coordination, Intragroup conflict, Intergroup encounters
1.
Altmann J (1974). Observational study of behavior: sampling methods. Behaviour 49: 227-267.
2.
Boinski S (1991). The coordination of spatial position: a field study of the vocal behaviour of adult female squirrel monkeys. Animal Behaviour 41: 89-102.
3.
Boinski S (1996). Vocal coordination of troop movement in squirrel monkeys (Saimiri oerstedi and S. sciureus) and white-faced capuchins (Cebus capucinus). In Adaptive Radiations of Neotropical Primates (Norconk M, Rosenberger AL, Garber P, eds.), pp 251-269. New York, Plenum Press.
4.
Bradbury JW, Vehrencamp SL (1998). The Principles of Animal Communication. Sunderland, Sinauer.
5.
Byrne RW (1981a). Distance vocalizations of guinea baboons (Papio papio) in Senegal: an analysis of function. Behaviour 78: 283-313.
6.
Byrne RW (1981b). Uses of long-range calls during ranging by Guinea baboons. In Primate Behaviour and Sociobiology (Chiarelli AB, Corruccini RS, eds.), pp 104-109. Berlin, Springer.
7.
Byrne RW (1982). Primate vocalizations: structural and functional approaches to understanding. Behaviour 80: 241-258.
8.
Byrne RW (1983). Bringing experimentation to the field of primate vocalization. In Perspectives in Primate Biology (Seth PK, Seth S, eds.), pp 71-81. New Delhi, Today and Tomorrow's Printers and Publishers.
9.
Caselli CB, Mennill DJ, Bicca-Marques JC, Setz EZ (2014). Vocal behavior of black-fronted titi monkeys (Callicebus nigrifrons): acoustic properties and behavioral contexts of loud calls. American Journal of Primatology 76: 788-800.
10.
Davies AG (1984). An Ecological Study of the Red Leaf Monkey (Presbytis rubicunda) in the Dipterocarp Forests of Sabah, Northern Borneo. PhD thesis, University of Cambridge.
11.
Davies AG (1991). Seed-eating by red leaf monkeys (Presbytis rubicunda) in dipterocarp forest of northern Borneo. International Journal of Primatology 12: 119-144.
12.
Delgado R (2006). Sexual selection in the loud calls of male primates: signal content and function. International Journal of Primatology 27: 5-25.
13.
Ehlers Smith D (2014). Preliminary evidence for the hired guns hypothesis and indirect mate defence in a wild group of maroon langurs Presbytis rubicunda (Muller, 1838) in Sabangau tropical peat-swamp forest, Central Kalimantan, Indonesian Borneo. Asian Primates Journal 4: 2-15.
14.
Ehlers Smith D, Ehlers Smith Y (2013). Population density of red langurs in Sabangau tropical peat-swamp forest, Central Kalimantan, Indonesia. American Journal of Primatology 75: 837-847.
15.
Ehlers Smith D, Ehlers Smith Y, Cheyne S (2013a). Home-range use and activity patterns of the red langur (Presbytis rubicunda) in Sabangau tropical peat-swamp forest, Central Kalimantan, Indonesian Borneo. International Journal of Primatology 34: 957-972.
16.
Ehlers Smith D, Husson SJ, Ehlers Smith Y, Harrison ME, Smith DA (2013b). Feeding ecology of red langurs in Sabangau tropical peat-swamp forest, Indonesian Borneo: extreme granivory in a nonmasting forest. American Journal of Primatology 75: 848-859.
17.
Fragaszy DM, Boinski S, Whipple J (1992). Behavioral sampling in the field: comparison of individual and group sampling methods. American Journal of Primatology 26: 259-275.
18.
Gautier JP (1998). La communication acoustique chez les primates. Bulletin de la Société zoologique 123: 239-253.
19.
Gautier JP, Gautier A (1977). Communication in Old World monkeys. In How Animals Communicate (Sebeok TA, ed.), pp 890-964. Bloomington, Indiana University Press.
20.
Gouzoules H, Gouzoules S (2002). Primate communication: by nature honest, or by experience wise? International Journal of Primatology 23: 821-848.
21.
Hart D (2007). Predation on primates: a biogeographical analysis. In Primate Anti-Predator Strategies (Gursky SL, Nekaris KAI, eds.), pp 27-59. New York, Springer.
22.
Hohmann G, Fruth B (1994). Structure and use of distance calls in wild bonobos (Pan paniscus). International Journal of Primatology 15: 767-782.
23.
Hohmann G, Fruth B (1995). Long-distance calls in great apes: sex differences and social correlates. In Current Topics in Primate Vocal Communication (Zimmerman E, Newman JD, Jürgens U, eds.), pp 161-184. New York, Plenum Press.
24.
Kinzey WG, Robinson JG (1983). Intergroup loud calls, range size, and spacing in Callicebus torquatus.American Journal of Physical Anthropology 60: 539-544.
25.
Kirkpatrick RC (2011). The Asian colobines: diversity among leaf-eating monkeys. In Primates in Perspective (Campbell CJ, Fuentes A, Mackinnon KC, Panger M, Bearder SK, eds.), 2nd ed., pp 189-202. Oxford, Oxford University Press.
26.
Maciej P, Ndao I, Hammerschmidt K, Fischer J (2013). Vocal communication in a complex multi-level society: constrained acoustic structure and flexible call usage in Guinea baboons. Frontiers in Zoology 10: 58.
27.
Marshall A (2004). Population Ecology of Gibbons and Leaf Monkeys across a Gradient of Bornean Forest Types. PhD thesis, Harvard University, Cambridge.
28.
Mitani JC, Marler P (1987). Vocal communication in primates and birds: parallels and contrasts. In Primate Vocal Communication (Todt D, Symaxes D, Goldeking R, eds.), pp 3-14. Berlin, Springer.
29.
Nijman V, Nekaris KA (2012). Loud calls, startle behaviour, social organisation and predator avoidance in arboreal langurs (Cercopithecidae: Presbytis). Folia Primatologica 83: 274-287.
30.
Paterson JD (2001). Primate Behaviour, 2nd ed. Long Grove, Waveland Press.
31.
Phillips Q, Phillips K (2014). Phillips' Field Guide to the Birds of Borneo, 3rd ed. Princeton, Princeton University Press.
32.
Robinson JG (1979). Vocal regulation of use of space by groups of titi monkeys (Callicebus moloch). Behavioral Ecology and Sociobiology 5: 1-15.
33.
Robinson JG (1981). Vocal regulation of inter- and intra-group spacing during boundary encounters in the titi monkey, Callicebus moloch. Primates 22: 161-172.
34.
Schel AM, Zuberbühler K (2012). Dawn chorusing in guereza colobus monkeys. Behavioral Ecology and Sociobiology 66: 361-373.
35.
Setchell JM, Curtis DJ (2011). Field and Laboratory Methods in Primatology, 2nd ed. Cambridge, Cambridge University Press.
36.
Seyfarth RM, Cheney DL, Marler P (1980). Monkey responses to three different alarm calls: evidence of predator classification and semantic communication. Science 210: 801-803.
37.
Spehar S, Delgado R (2012). Ranging patterns of red langurs (Presbytis rubicunda) in East Kalimantan, Indonesia. American Journal of Physical Anthropology 147(S54): 275.
38.
Spehar S, Di Fiore A (2013). Loud calls as a mechanism of social coordination in a fission-fusion taxon, the white-bellied spider monkey (Ateles belzebuth). Behavioral Ecology and Sociobiology 67: 947-961.
39.
Steenbeek R (1999). Tenure related changes in wild Thomas's langurs. I. Between-group interactions. Behaviour 136: 595-625.
40.
Struhsaker T (1967). Auditory communication in vervet monkeys (Cercopithecus aethiops). In Social Communication among Primates (Altman SA, ed.), pp 281-324. Chicago, University of Chicago Press.
41.
Supriatna J, Manullang BO, Soekara E (1986). Group composition, home range, and diet of the maroon leaf monkey (Presbytis rubicunda) at Tanjung Puting Reserve, Central Kalimantan, Indonesia. Primates 27: 185-190.
42.
Wich SA, Assink PR, Becher F, Sterck EHM (2002). Playbacks of loud calls to wild Thomas langurs (Primates; Presbytis thomasi): the effect of familiarity. Behaviour 139: 79-87.
43.
Zuberbühler K (2001). Predator-specific alarm calls in Campbell's monkeys, Cercopithecus campbelli. Behavioral Ecology and Sociobiology 50: 414-422.
© 2016 S. Karger AG, Basel
2016
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.