Morphological change in an isolated population of red squirrels (Sciurus vulgaris) in Britain

Chandler, K. E., Gálvez-López, E. ORCID: https://orcid.org/0000-0002-6211-966X, Black, S. ORCID: https://orcid.org/0000-0003-1396-4821, Kitchener, A. C. ORCID: https://orcid.org/0000-0003-2594-0827, Hamill, K. ORCID: https://orcid.org/0000-0002-0809-9338, Roberts, B., Doherty, S. ORCID: https://orcid.org/0000-0002-5503-2734 and Cox, P. G. ORCID: https://orcid.org/0000-0001-9782-2358 (2025) Morphological change in an isolated population of red squirrels (Sciurus vulgaris) in Britain. Royal Society Open Science, 12 (1). 240555. ISSN 2054-5703 doi: 10.1098/rsos.240555

Abstract/Summary

The mechanical properties of dietary items are known to influence skull morphology, either through evolution or by phenotypic plasticity. Here, we investigated the impact of supplementary feeding of peanuts on the morphology of red squirrels ( Sciurus vulgaris ) from five populations in Britain (North Scotland, Borders, Jersey and two temporally distinct populations from Formby (Merseyside)). Stable isotope analysis confirmed dietary ecology in 58 specimens. Geometric morphometrics were used to analyse three-dimensional and two-dimensional shape variation across 113 crania and 388 mandibles, respectively. Nitrogen isotope ratios (δ 15 N) were lower in the 1990s and 2010s Formby squirrels (suggesting a diet with an increased proportion of peanuts), and higher in other populations. Significant differences in cranio-mandibular shape were found between all populations, with 1990s Formby red squirrels exhibiting a morphology associated with reduced masticatory efficiency. This effect was partially reversed following a reduction in supplementary feeding of peanuts. We propose that these morphological changes are related to the reduced mechanical effort needed to process peanuts relative to naturally occurring food items. This could be an example of diet-induced plastic changes to the skeleton in non-muroid wild mammals, although further research is needed to exclude other driving factors such as genetics.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/120396
Item Type	Article
Refereed	Yes
Divisions	Science > School of Archaeology, Geography and Environmental Science > Department of Geography and Environmental Science
Publisher	The Royal Society
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