Acoustical communication among free‐ranging common Indian langurs (Presbytis entellus) in two different habitats of North India

Abstract

Acoustical signals of free-ranging Presbytis entellus were analyzed with the aid of sonagrams. Tape-recordings were from two ecologicallydifferent habitats in North India, the Kumaon Hills on the southern slope of the Himalayas and the plains habitat of Rajasthan. The acoustical quality and the spectrographic structure of the signals are described and their communicative functions within the social context discussed. We found significant differences in the acoustical repertoire of the langurs of the two habitats both in the tone quality and the spectrographical structure of single signals serving the same functions in both regions and in functional deviations of identically or similarly structured vocalizations. Some of these differences appear to be phylogenetic adaptations to the different environmental conditions of the habitats or to be related to special types of social organization in the two separate langur populations.

Vocal Communication in Lion-Tailed Macaques (Macaca silenus)

“…During teeth grinding, the mouth is almost closed (teeth covered by lips) and only the alternat ing, masticating motions are visible. Teeth grinding by lion-tailed macaques is compara ble to that by langurs [Poirier, 1970;Vogel 1973; our own observations] and perhaps similar to 'teeth gnashing' by rhesus monkeys [Altmann, 1962;Rowell and Hinde, 1962], (2) Jumping and shaking combine acous tic as well as visual signals and are common in many other primate species [see summa rized representation by Gautier and Gautier, 1977]. They differ from common locomo tions or motions on account of their high fre quency and amplitude as well as contrast accentuation.…”

“…Vogel [1973] revealed differences in the vocal repertoire and vocal behaviour of com mon langurs (Presbytis entellus) depending on habitats. Brown and Waser [1984] showed for blue monkeys (Cercopithecus mitis) that vocalization as well as perception of acoustic signals are adapted to specific bioacoustic sound transmission conditions in their rain forest habitat.…”

Acoustically Dimorphic Advertisement Calls Separate Morphologically and Genetically Homogenous Populations of the Grey Mouse Lemur (Microcebus murinus)

“…Population-specific differences in the vocalisations of non-human primates that could be termed dialects in the latter sense have scarcely been found, yet. The studied populations either differed in morphological features and are regarded as different subspecies (squirrel monkeys [8]; langurs [9]; tamarins [10]) or were geographically separated (Japanese monkeys [11]; langurs [12]; chimpanzees [13]). Differences in vocalisations between neighbouring populations that were not separated by a geographic barrier have been reported only for the long call of one species, the red-chested moustached tamarin, Saguinus l. labiatus [14].…”

Recruitment and monitoring behaviors by leaders predict following in wild Barbary macaques (<i>Macaca sylvanus</i>)

“…In our analyses we ignored the role of vocalizations which in some species can function as cues or signals during group coordination (e.g., Hanuman langurs, Vogel, 1973;guerezas, Oates, 1977;pygmy marmosets, Soini, 1981;yellow baboons, Papio cynocephalus, Norton, 1986;chacma baboons, Fischer and Zinner, 2011b; red-fronted lemurs, Eulemur rufifrons, Pflüger and Fichtel, 2012; woolly lemurs, Avahi occidentalis, Ramanankirahina et al, 2015). In our case, however, only 5 % of collective movements were associated with grunt vocalizations by the initiator of the movement or other group members and these were equally frequent during successful and unsuccessful initiations.…”