Differences in boldness between Eurasian and American wolves (Canis lupus) might be based on adaptive mechanisms

Boldness - defined as the propensity of individuals to take risks - is a key research area within animal behavioural studies, significantly affecting adaptive strategies, habitat selection, foraging behaviour, reproduction, dispersal, and other crucial survival behaviours. Despite the extensive study of personality traits like extraversion and curiosity across various animal species, data on wolves (Canis lupus), particularly on the subspecies level, remains sparse. This study aims to bridge this gap by examining boldness and its associated personality traits in different wolf subspecies (Canis lupus lupus, Canis lupus arctos, Canis lupus lycaon) (n = 23), and wolf-dog hybrids (n = 10), utilising novel object interaction tests and validated questionnaires previously applied to wild canids. Our results show significant differences in boldness as well as in related personality traits between taxa, both between pure wolves and wolf hybrids, with significantly higher boldness of North American subspecies. The inter-subspecies differences were more significant than the differences between groups or at the individual level, suggesting that subspecies ecology and historical selection pressure in subspecies history might have caused long-lasting adaptations in Canis lupus ssp.