Englund J.K.Å. 2020. The function of the dewclaw in the Scandinavian red fox (Vulpes vulpes) // Russian J. Theriol. Vol.19. No.2. P.172–177 [in English].
Jan K. Å. Englund [je.fox@swipnet.se], Kattfotsbacken 16, S-165 73 Hässelby, Sweden.
doi: 10.15298/rusjtheriol.19.2.07
ABSTRACT. In foxes, Vulpes vulpes, the dewclaw sits on the forelimb a bit up from the ground. It is usually thought to be functionless. The length of metacarpal 1 and metacarpal 3, as well as the relation between them (Mc1 / Mc3), increases northwards from Denmark to northern Sweden. If it were the same physio- logical system regulating the growth of all the metacarpal bones, they would increase at the same ratio and the long metacarpal 3 (43–64 mm) would therefore increase northwards in absolute length more than the shorter metacarpal 1 (13–20 mm). In this case the dewclaw in northern foxes would be set higher above the ground than in southern ones. If measured as a percentage, however, the mean length of metacarpal 1 shows a larger increase northwards than that of the other metacarpal bones. The tip of the nail of the dewclaw in foxes is shown to be 12–15 mm above the ground in all areas in Scandinavia, and the dewclaw is therefore considered to have an important function. It is believed to increase the effectiveness of hunting voles, when the dewclaws will hit the back of the prey.
KEY WORDS: anatomical adaptation, dewclaw, metacarpal, red fox, Vulpes vulpes.