Paedomorphic Facial Expressions Give Dogs a Selective Advantage

Bridget M Waller,Anne M Burrows,Kate Peirce,Cátia C Caeiro,Sandra Mccune,Juliane Kaminski,Linda Scheider,Claire Wade

doi:10.1371/journal.pone.0082686

Bridget M Waller, Anne M Burrows + Show 6 more

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https://doi.org/10.1371/journal.pone.0082686

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Abstract

How wolves were first domesticated is unknown. One hypothesis suggests that wolves underwent a process of self-domestication by tolerating human presence and taking advantage of scavenging possibilities. The puppy-like physical and behavioural traits seen in dogs are thought to have evolved later, as a byproduct of selection against aggression. Using speed of selection from rehoming shelters as a proxy for artificial selection, we tested whether paedomorphic features give dogs a selective advantage in their current environment. Dogs who exhibited facial expressions that enhance their neonatal appearance were preferentially selected by humans. Thus, early domestication of wolves may have occurred not only as wolf populations became tamer, but also as they exploited human preferences for paedomorphic characteristics. These findings, therefore, add to our understanding of early dog domestication as a complex co-evolutionary process.

Highlights

Wolves were domesticated early in the history of human civilization [1], and have since evolved into dogs whose lives are inextricably linked to those of humans
From the regression equation (y = 114.12x20.515, see Table 4) we can predict that a dog that produces five AU101 during the 2 min observation will stay in the shelter for 49.83 days on average, but if it produces 10 AU101, this would be reduced to 34.88 days, and if it produces 15, this would be reduced to 28.31 days
Domestic dogs who produced a high frequency of facial movement to raise the inner brow (AU101) were adopted more quickly from re-homing shelters

Summary

Introduction

Wolves were domesticated early in the history of human civilization [1], and have since evolved into dogs whose lives are inextricably linked to those of humans. One hypothesis suggests that wolves underwent a process of selfdomestication as tamer individuals took advantage of opportunities to scavenge from human settlements during the agricultural revolution [2]. In support of this theory is recent evidence that domestic dogs exhibit genetic mutations to a starch-rich diet [3]. In many ways dogs appear more like wolf puppies than wolf adults These features are thought to have evolved as a byproduct of the domestication process, and arose accidently when aggression was actively selected against [6,7], for a detailed review see [8]

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