ABSTRACT
The jaw system in canids is essential for defence and prey acquisition. However, how it varies in wild species in comparison with domestic species remains poorly understood, yet is of interest in terms of understanding the impact of artificial selection. Here, we explored the variability and interrelationships between the upper and lower jaws, muscle architecture and bite force in the red fox (Vulpes vulpes). We performed dissections and used 3D geometric morphometric approaches to quantify jaw shape in 68 foxes. We used a static lever model and bite force estimates were compared with in vivo measurements of 10 silver foxes. Our results show strong relationships exist between cranial and mandible shape, and between cranial or mandible shape on the one hand and muscles or estimated bite force on the other hand, confirming the strong integration of the bony and muscular components of the jaw system. These strong relationships are strongly driven by size. The functional links between shape and estimated bite force are stronger for the mandible, which probably reflects its greater specialisation towards biting. We then compared our results with data previously obtained for dogs (Canis lupus familiaris) to investigate the effect of domestication. Foxes and dogs differ in skull shape and muscle physiological cross-sectional area (PCSA). They show a similar amount of morphological variation in muscle PCSA, but foxes show lower variation in cranial and mandible shape. Interestingly, the patterns of covariation are not stronger in foxes than in dogs, suggesting that domestication did not lead to a disruption of the functional links of the jaw system.
Footnotes
Competing interests
The authors declare no competing or financial interests.
Author contributions
Conceptualization: C.B., M.M., C.C., R.C., A.H.; Methodology: C.B., M.M., C.H., R.C., A.H.; Software: C.B., M.M., R.C.; Validation: C.B., M.M.; Formal analysis: C.B., M.M.; Investigation: C.B., M.M., C.H., R.C., A.H.; Resources: E.M., C.G., J.B., H.G., A.L., R.T.; Data curation: C.B.; Writing - original draft: C.B., A.H.; Writing - review & editing: C.B., A.H., E.M., C.G., R.T.; Visualization: C.B.; Supervision: C.C., R.C., A.H.; Project administration: C.C., R.C., A.H.; Funding acquisition: C.C., A.H.
Funding
This research was funded by the Ministère de l'Enseignement supérieur, de la Recherche et de l'Innovation.
Supplementary information
Supplementary information available online at https://jeb.biologists.org/lookup/doi/10.1242/jeb.224394.supplemental
- Received March 2, 2020.
- Accepted January 28, 2021.
- © 2021. Published by The Company of Biologists Ltd
Log in using your username and password
Log in through your institution
Pay Per Article - You may access this article (from the computer you are currently using) for 1 day for US$30.00 .
Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.