Why do European stoats Mustela erminea not follow Bergmann's rule?

• Published in: Ecography
• Main Author: Erlinge, Sam
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1987
• Subjects: Ecology, Evolution, Behavior and Systematics; Northern Sweden
• Online Access: http://dx.doi.org/10.1111/j.1600-0587.1987.tb00735.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1600-0587.1987.tb00735.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0587.1987.tb00735.x

Stoat Mustela erminea body size shows remarkably great variation over the species' European range. The pattern of this variation is opposite to that suggested by Bergmann's rule, i.e., stoats in central Europe are significantly larger than those in southern Sweden which, in turn are considerably larger than their conspecifics in northern Sweden. Neither winter temperature nor the length of snow cover shows any consistent correlation with stoat body size variation, and the larger body size of the southern populations could not be related to a widening of the stoat's feeding niche. A positive correlation was found between the frequency distribution, by size, of available prey and stoat body size in the different areas examined. This supports the hypothesis that body size variation in the stoat, especially females, is an adjustment to regional variations in the sizes of their available prey.