A new perspective on barking in dogs (Canis familaris.).

Abstract

The disparity in bark frequency and context between dogs (Canis familiaris) and wolves (Canis lupus) has led some researchers to conclude that barking in the domestic dog is nonfunctional. This conclusion attributes the differences primarily to genetic variation caused by domestication rather than to the influence of social environment on ontogeny. Other researchers, however, have concluded that vocal usage and response to vocalizations in mammals are strongly guided by social interactions. Closer evaluation of dog vocalizations with respect to social environment reveals developmental factors that lead to both frequent barking and barking in many contexts. Additionally, spectrographic analysis indicates that bark structure varies predictably with context, suggesting that barks can be divided into contextual subtypes and may be a more complex form of communication than given credit.

Auditory Communication in Domestic Dogs

“…Another, better understood, outcome is the effect of arousal on F0 in the context of broadcasting of motivational state information. Domestic dog barks occur on a graded frequency scale: lower peak, mean, and range of F0 are found in barks recorded in an aggressive situation than in those recorded in a playful situation (Feddersen-Petersen, 2000;Yin, 2002). This has been confirmed in single-breed and mixed-breed experiments ) and is sufficiently predictive that barks can be reliably categorised as aggressive or playful on the basis of statistical analysis (Yin & McCowan, 2004).…”

“…It is also important to note that many studies to date have focussed on a single breed (e.g., Hungarian mudi; Pongrácz et al, 2005Marós et al, 2008) or a very small sample resulting in a limited number of breeds (e.g., ten dogs; Yin, 2002;Yin & McCowan, 2004). Because the range of morphological and behavioural variation between different dog breeds is so great, this might have led to biased representations of the occurrence and communicative content of dog vocalisations.…”

“…One outcome of this is that these temporal characteristics can be affected by state of arousal. Indeed, in barks and growls, inter-call interval and call duration are affected by production context: barks recorded in an aggressive context (being approached by a stranger) were found to have very short inter-bark intervals compared to barks recorded in a playful context (Yin, 2002), whereas growls recorded in an aggressive context are characterised by a low calling rate and have long call durations . Temporal characteristics might thus provide a guide to motivational state, although the salience of this to listeners is yet to be established.…”

“…Whilst dogs do not appear to modify the formant frequency scaling in their vocalisations, and thus only seem to provide a static indication of body size, they are able to produce an impressive range of F0 both within and between calls (Yin, 2002). Variations in the source signal may provide reliable information about the affective state of callers because it is influenced by changes to rate of respiration and/or muscular tension in the vocal folds (Hauser, 2000;Bachorowski & Owren, 2008), both of which are linked to physiological arousal.…”

“…On an individual level, F0 is influenced by changes to respiration and muscular control of the tension of the vocal folds. Therefore, F0 is highly variable both within and between calls, across individuals, and across breeds (Feddersen-Petersen, 2000;Yin, 2002;Taylor et al, 2008).…”