Factors of Polymorphism of Craniometric Characters in the Red Fox (Vulpes vulpes, Carnivora, Canidae) from the Center of European Russia

Abstract

Craniometry was investigated in four samples of the red fox (Vulpes vulpes L. 1758) (n = 403) from Tver oblast. Factors affecting the metric polymorphism of the fox skull can be presented in the following order according to their significance: age, sex, geographic, and chronographic variability. The geographic and chronographic factors are correlated with the jaws and teeth. An analysis of the time interval from the early 1990s to the present shows a weak trend toward an increase in some cranial structures. However, the inclusion of material from the 1980s reveals a more complex trend in the chronographic variability with size fluctuations. This may be due to the high rate of mortality which determines the stochastic nature of the chronographic size variability. The spatial variability of odontological and craniometric characters can be of adaptive functional significance.