Size communication in domestic dog, Canis familiaris, growls

Size Communication in Dogs

A.M. Taylor, D. Reby, K. McComb

Size communication in domestic dog, Canis familiaris, growls

Animal Behaviour, Volume 79, Issue 1, January 2010, Pages 205–210

ABSTRACT

In many species, body size is a key determinant of the outcome of agonistic interactions, and receivers are expected to attend to size cues when assessing competitors' signals. Several mammal vocalizations, including domestic dog growls, encode reliable information about caller body size in the dispersion of formant frequencies. To test whether adult domestic dogs attend to formant dispersion when presented with the growls of their conspecifics, we played recordings of resynthesized growls where the size-related variation in formant frequency spacing was manipulated independently of all other parameters. Subjects from three different size groups (small, medium and large dogs) were presented with playbacks of growls where formant frequencies had been rescaled to correspond to a dog 30% smaller or 30% larger than themselves. While large dogs systematically displayed more motivation to interact when growls simulated a smaller intruder, small dogs did not respond differentially to the playback conditions. However, the small dogs responded significantly less than all other size groups to both playback conditions. Our results suggest that domestic dogs are able to perceive size-related information in growls, and more specifically that they are able to adapt their behavioural response as a function of the perceived intruder's size relative to their own.

Physical size matters in the domestic dog's (Canis lupus familiaris) ability to use human pointing cues

William S. Helton, Nicole D. Helton

Physical size matters in the domestic dog's (Canis lupus familiaris) ability to use human pointing cues

Behavioural Processes, Volume 85, Issue 1, September 2010, Pages 77–79

Abstract

Researchers have reported differences between breeds of dogs in their ability to utilize human gestures (Wobber et al., 2009). These reports could either be the result of underlying differences in inherent communication abilities or differences in physical capacities amongst breeds. One physical difference between breeds which may make a difference in using visual cues is relative size. Larger dogs should, all other things being equal, have greater inter-ocular distances and this may improve their visual abilities for some tasks. This hypothesis was tested in the present study by comparing the performance of larger (>22.7 kg) and smaller (<22.7 kg) dogs on a pointing choice task. Larger dogs did perform better on this task than smaller dogs (P = .03). Researchers need to be careful when making comparisons between breeds to first consider physical differences before assuming any inherent cognitive differences.

Size communication in domestic dog, Canis familiaris, growls

A.M. Taylor, D. Reby, K. McComb

Size communication in domestic dog, Canis familiaris, growls

Animal Behaviour, Volume 79, Issue 1, January 2010, Pages 205–210

Abstract

In many species, body size is a key determinant of the outcome of agonistic interactions, and receivers are expected to attend to size cues when assessing competitors' signals. Several mammal vocalizations, including domestic dog growls, encode reliable information about caller body size in the dispersion of formant frequencies. To test whether adult domestic dogs attend to formant dispersion when presented with the growls of their conspecifics, we played recordings of resynthesized growls where the size-related variation in formant frequency spacing was manipulated independently of all other parameters. Subjects from three different size groups (small, medium and large dogs) were presented with playbacks of growls where formant frequencies had been rescaled to correspond to a dog 30% smaller or 30% larger than themselves. While large dogs systematically displayed more motivation to interact when growls simulated a smaller intruder, small dogs did not respond differentially to the playback conditions. However, the small dogs responded significantly less than all other size groups to both playback conditions. Our results suggest that domestic dogs are able to perceive size-related information in growls, and more specifically that they are able to adapt their behavioural response as a function of the perceived intruder's size relative to their own.