Describing whisker morphology of the Carnivora
G. Dougill, C.A. Brassey, E.L. Starostin, H. Andrews,
A. Kitchener, G.H.M. van der Heijden, V.G.A. Goss, R.A. Grant
One of the largest ecological transitions in carnivoran evolution was the
shift from terrestrial to aquatic lifestyles, which has driven morphological
diversity in skulls and other skeletal structures. In this paper, we
investigate the association between those lifestyles and whisker morphology.
However, comparing whisker morphology over a range of species is challenging
since the number of whiskers and their positions on the mystacial pads vary
between species. Also, each whisker will be at a different stage of growth
and may have incurred damage due to wear and tear. Identifying a way to
easily capture whisker morphology in a small number of whisker samples would
be beneficial. Here, we describe individual and species variation in whisker
morphology from two dimensional scans in red fox, European otter and grey
seal. A comparison of long, caudal whiskers shows inter species differences
most clearly. We go on to describe global whisker shape in 24 species of
carnivorans, using linear approximations of curvature and taper, as well as
traditional morphometric methods. We also qualitatively examine surface
texture, or the presence of scales, using scanning electron micrographs. We
show that gross whisker shape is highly conserved, with whisker curvature
and taper obeying simple linear relationships with length. However, measures
of whisker base radius, length, and maybe even curvature, can vary between
species and substrate preferences. Specifically, the aquatic species in our
sample have thicker, shorter whiskers that are smoother, with less scales
present than those of terrestrial species. We suggest that these thicker
whiskers may be stiffer and able to maintain their shape and position during
underwater sensing, but being stiffer may also increase wear.
keywords: aquatic, curvature, mechanoreception, touch, vibrissae
Journal of Morphology 284, e21628 (2023)
[https://doi.org/10.1002/jmor.21628]