(Canis Lupus Dingo) Acoustic Repertoire: Form and Contexts

Behaviour 150 (2013) 75–101 brill.com/beh

Dingo (Canis lupus dingo) acoustic repertoire: form and contexts

Éloïse C. Déaux ∗ and Jennifer A. Clarke Department of Biological Sciences, Macquarie University, Sydney, NSW 2122, Australia *Corresponding author’s e-mail address: [email protected]

Accepted 5 November 2012

Abstract The classification and description of a species’ acoustic repertoire is critical to our understanding of broader behavioural patterns and provides data for future cross-species comparative studies. To date, our understanding of canid auditory communication remains limited as full acoustic repertoires have been compiled for only nine of 36 extant species. Dingoes (Canis lupus dingo)are apex predators in Australia, and while their ecology and life-history patterns have been extensively studied, their communication system remains poorly understood. Early studies noted four sound types, but whether this represented the dingoes’ full range of laryngeal and nasal sounds was unknown. We aimed to quantitatively and qualitatively describe the full acoustic repertoire of dingoes. We identified nine discrete vocalisations (i.e., laryngeal sounds) and two nasal sounds. Of these nine vocalisations, five were previously identified as common to other canid species. This study also revealed that dingoes possess a graded acoustic communication system, where the gradual change in acoustic characteristics of discrete vocalisations was noted. Dingoes also uttered ‘mixed sounds’, a finding in concordance with previous studies of social canids. Additionally, we established an ethogram to further our understanding of the contexts in which dingo acoustic communication occurs. Keywords Canidae, dingo, acoustic repertoire, ethogram, cross-species comparisons.

1. Introduction The quantitative classiﬁcation and description of acoustic repertoires is use- ful in gaining a better understanding of a species’ behavioural patterns (Robbins, 2000) per se. In addition, it also provides data for cross-species comparisons, which are essential to our understanding of the evolution of communication systems and associated life-history traits. For instance, Co- hen & Fox (1976) discuss the effect of domestication on canid vocalisations

Table 1. Number of adult sounds described for dingoes and those canid species whose full vocal repertoires have been compiled.

Species Number of sounds Reference

Dingo (C. lupus dingo) 4 Corbett & Newsome (1975); Corbett (2001) Coyote (C. latrans) 11 Lehner (1978) Timber wolf (C. lupus) 11 Schassburger (1993) Red wolf (C. rufus) 7 McCarley (1978) African wild dog (Lycaon pictus) 11 Robbins (2000) Dhole (Cuon alpinus) 11 Volodin et al. (2001) Bush dog (Speothos venaticus) 8 Brady (1981) Crab-eating fox (Cerdocyon thous) 6 Brady (1981) Maned wolf (Chrysocyon brachyurus) 8 Brady (1981) Red fox (Vulpes vulpes) 12 Newton-Fisher et al. (1993) based on the comparisons of vocal repertoires of dogs (Canis familiaris)and other canids. It has also been proposed that increased sociality is associated with an increased complexity of the acoustic communication system in canids and in mustelids (Cohen & Fox, 1976; Wong et al., 1999, respec- tively). However, comparative studies are limited by the amount of data available for closely related species. In canids, acoustic repertoires (which may include laryngeal and nasal sounds) have been compiled for only nine out of 36 extant species (Table 1). Clearly, there is a need for additional repertoires to be assembled, to gain knowledge at the species and higher levels of organization (Schassburger, 1993). The dingo, C. lupus dingo, is one of the canid species whose auditory communication system remains poorly understood. In a preliminary analy- sis, Corbett & Newsome (1975) qualitatively described three vocalisations: ‘howls’, ‘bark-howls’ and ‘moans’. Howling was hypothesized to serve lo- cating individuals whether to repel or attract them and bark-howls were suggested to serve as warning signals about immediate threats (Corbett & Newsome, 1975; Thomson, 1992a). Moans were recorded from individuals approaching waterholes and were proposed to function as alerting signals announcing the caller’s approach. Later, Corbett (2001) added a nasal sound termed a ‘snuff’, which was suggested to aid gaining information about the environment but was not proposed to possess a communicative function. None of these hypotheses have been investigated.