Quantity discrimination in canids: Dogs (Canis familiaris) and wolves (Canis lupus) compared

• Published in: Behavioural processes Vol. 144; pp. 89 - 92
• Main Authors: Miletto Petrazzini, Maria Elena, Wynne, Clive D.L.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2017; Elsevier Science Ltd
• Subjects: Animal behavior; Animals; Canidae; Canis lupus; Discrimination; Discrimination (Psychology) - physiology; Dogs; Domestication; Food; food choices; Food Preferences - physiology; Interspecific; interspecific variation; Judgment - physiology; Pets; Quantity discrimination; Species; Spontaneous choice; Variables; Wolves; Quantity discrimination; Wolves; Spontaneous choice; Dogs
• ISSN: 0376-6357; 1872-8308; 1872-8308
• DOI: 10.1016/j.beproc.2017.09.003

•Dogs and wolves were presented with a spontaneous choice between two sets containing different quantities of food items.•Four numerical contrasts with increasing numerical ratio were presented: 1 vs. 3, 2 vs. 4, 2 vs. 3 and 3 vs. 4.•Dogs’ accuracy was affected by the numerical ratio, while no ratio effect was found in wolves.•These results suggest the existence of different quantitative abilities in dogs and wolves. Accumulating evidence indicates that animals are able to discriminate between quantities. Recent studies have shown that dogs’ and coyotes’ ability to discriminate between quantities of food items decreases with increasing numerical ratio. Conversely, wolves’ performance is not affected by numerical ratio. Cross-species comparisons are difficult because of differences in the methodologies employed, and hence it is still unclear whether domestication altered quantitative abilities in canids. Here we used the same procedure to compare pet dogs and wolves in a spontaneous food choice task. Subjects were presented with two quantities of food items and allowed to choose only one option. Four numerical contrasts of increasing difficulty (range 1–4) were used to assess the influence of numerical ratio on the performance of the two species. Dogs’ accuracy was affected by numerical ratio, while no ratio effect was observed in wolves. These results align with previous findings and reinforce the idea of different quantitative competences in dogs and wolves. Although we cannot exclude that other variables might have played a role in shaping quantitative abilities in these two species, our results might suggest that the interspecific differences here reported may have arisen as a result of domestication.