A 2021 study, published in Scientific Reports, investigates the effects of domestication on the craniofacial skeletal morphology of silver foxes. Using three-dimensional geometric morphometrics (GM) alongside linear and endocranial measurements, the researchers compared domesticated (selected) and unselected foxes from the renowned Russian Farm-Fox Experiment with wild foxes from the original population from which the farm foxes were bred.
Interestingly, the findings revealed that domesticated and unselected foxes displayed minimal differences in craniofacial shape and size. However, the wild foxes differed significantly from both groups of farmed foxes. Wild foxes showed less cranial base flexion, relatively larger cranial vaults, and greater endocranial volumes.
These results challenge previous assumptions, particularly the idea that unselected foxes in the Russian Farm-Fox Experiment serve as a valid proxy for wild foxes when studying craniofacial morphology. It suggests that future research on domestication syndrome must include wild populations to better understand the phenotypic effects of different selection pressures. Moreover, the study highlights that increased docility in domesticated foxes cannot be reliably identified through craniofacial skeletal shape differences alone.
Implications
The study’s findings suggest that while domestication may impact behaviour, it does not necessarily lead to easily identifiable craniofacial changes. This calls into question some assumptions about the biological markers of domestication syndrome and emphasises the complexity of phenotypic changes resulting from domestication. Furthermore, it underlines the importance of including wild populations in comparative studies to avoid oversimplifying the effects of selection pressures on domesticated animals. This work may inspire more nuanced approaches in future research on the physical and behavioural changes that occur in species through the process of domestication.
Summary
The 2021 study by Kistner et al. explored the effects of domestication on the craniofacial skeletal morphology of silver foxes using 3D geometric morphometrics and various measurements. By comparing domesticated, unselected, and wild foxes, the researchers found minimal differences between domesticated and unselected foxes but significant differences between wild foxes and both groups of farmed foxes.
Wild foxes had less cranial base flexion, larger cranial vaults, and greater endocranial volumes. These findings challenge the assumption that unselected farm foxes can be used as stand-ins for wild foxes in studies of craniofacial morphology.
The study highlights the need to include wild populations in future domestication research and suggests that behavioural traits like docility are not reliably reflected in craniofacial changes.
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