Is the British squirrel (Sciurus vulgaris leucourus Kerr) British?

Abstract

Abstract The form of squirrel described as the British race is reputedly amongst the most easily distinguished of all the races of Sciurus vulgaris , having ear tufts and tail which bleach to a milky whiteness during the summer months. Today most squirrels in the British Isles appear to be variable in colour. The aim of this project was to discover if S. v. leucourus possessed a distinctive skull shape. Differences in skull shape due to age were insignificant in comparison with those due to sex; therefore all age classes were pooled and analysed according to sex by multivariate methods. Apart from S. v. argenteus and 5. v. mantchuricus , of which there was insufficient material, only S. v. lis demonstrated a clear‐cut discontinuity from the other subspecies in both sexes. Skulls of the Persian squirrel ( Sciurus anomalus ), the most closely related species, were distinguishable from vulgaris only in the females. The subspecies S. v. lis , on the basis of skull shape, therefore appeared to have better claims to specific rank. S. v. fuscoater was the most heterogeneous in skull shape of all the subspecies analysed. S. v. leucourus was second and overlapped the distribution of ten of the other seventeen subspecies. Of the British Museum's collection of S. v. leucourus (1879–1935) 38% had skull shapes unique to the subspecies. By contrast none of the skulls collected by the Forestry Commission (1972‐74) differed in shape from other subspecies, though 8/14 were of the light‐tailed variety. Moreover, only one of the twelve squirrels with bleached tails in the B.M. collected before 1913 was distinguishable from S. v. fuscoater on skull shape, and then only marginally. The seven skulls in the B.M. which differed most markedly from other races had skins which were indistinguishable from the red form of squirrel on the continent. Therefore S. v. leucourus may describe a sport rather than a subspecies.