Characterising the vocal repertoire of the Indian wolf (Canis lupus pallipes)

Abstract

38 Vocalisation plays a critical role in social animals for conveying information on 39 foraging, reproductive, and social behaviours [1][2][3][4][5][6][7]. Characterising the vocal repertoire 40 of a species provides a base for understanding the behavioural significance of different 41 vocalisations and studying how vocal communication varies across the populations, 3 42 subspecies, and taxa [8][9][10]. The wolf (Canis lupus) is a social mammal and uses a 43 variety of vocalisations for communication. Being present throughout Eurasia and North 44 America, the wolf is one of the most widely distributed land mammals and occupies a 45 wide range of different habitat types [11]. The Indian wolf is among the smallest [12] 46 and one of the most evolutionarily distinct wolf subspecies, having diverged around 47 270,000 and 400,000 years ago based on mitochondrial DNA [13][14][15]. Studying the 48 vocal repertoire of the Indian wolf can aid in future studies on the function of different 49 vocal signals in Indian wolves and, more broadly, the variation in vocalisation across 50 subspecies and taxa within the Canis clade.51 The best-known wolf vocalisation -the howl -is a long-range harmonic call used for 52 territorial advertising and social cohesion [1,[16][17][18]. Recent studies have shown 21 53 different howl types across various canid subspecies based on quantitative similarity in 54 modulation pattern [8]. Along with howl, wolves also communicate using 7 to 12 other 55 harmonic calls, which is a clear pitch sound wave that possesses multiple integral 56 frequencies [19][20][21]. Many of these other harmonic vocalizations are short-ranged, and 57 due to difficulties in recording these calls, remain less studied compared to the wolf 58 howl [22]. These short-ranged calls are important for communicating passive or 59 aggressive behaviour among social canids [22][23][24].60 The whimper, whine and yelp are various calls for communicating passive and friendly 61 behaviour among wolves [18,23], whereas noisy calls, which don't have a clear pitch or 62 distinct frequency band in their spectrograms, communicate different levels of 63 aggression [18,23]. The whimper and whine vocalization is similar to a crying sound 64 with the whimper having a comparatively shorter duration than whine [18,25]. The 65 whine vocalization is mostly used for submissive behaviour whereas the whimper is 4 66 primarily used for greeting [18]. Yelp is a short and sharp cry and is used in submissive 67 behaviour with body contacts [18,25]. To communicate different levels of aggression 68 behaviors, wolves use noisy calls which consist of the growl, woof, and bark. Growl is a 69 laryngeal sound to show dominance in any interaction, whereas the woof vocalization is 70 a non-vocal sound cue (without involvement of vocal cords) used by adults for their 71 pups [18,25,26]. The bark is a short low pitched sound with rapid frequency modulation 72 and is used during aggressive defence [19,26], such as defending pups or defending a 73 food resource. Wo...