Growth and sexual dimorphism of craniometric measurements of the red fox (Vulpes vulpes L.) in Transcarpathia

Abstract

Purpose of the work. This study investigates sexual dimorphism in the red fox (Vulpes vulpes) population of Zakarpattia based on the analysis of 75 skulls from the Zoological Museum of Uzhhorod National University. To address existing gaps in knowledge, 26 cranial measurements were evaluated with consideration of both age and sex. This approach enabled the assessment of growth dynamics, the characterization of morphological variation, and the identification of key features of sexual dimorphism within the population. The results provide baseline data for future studies and contribute to a broader understanding of intraspecific variation across the species’ range. Methodology. Craniometric traits were analyzed across different sexes and age groups. Statistical analyses were conducted using SPSS, PAST, and MS Excel. Both univariate and multivariate analyses of variance (ANOVA) were applied, revealing significant differences between sexes and among age groups. Additionally, Principal Component Analysis (PCA) was performed to identify the measurements contributing most to overall variation. Scientific novelty. The study provides essential morphometric baseline data for red foxes in a poorly studied region and improves understanding of intraspecific variability. The findings emphasize the combined influence of growth patterns, sexual selection, and ecological factors in shaping cranial sexual dimorphism. Conclusions. Cranial growth was most pronounced up to 5–6 months of age, followed by a slowdown and occasional negative increments. The results suggest that sexual dimorphism in this population is primarily shaped by sexual selection and male–male competition, with larger males potentially having a reproductive advantage. At the same time, environmental constraints, particularly food availability, may limit excessive body size, leading to an optimal size range shared by both sexes. Size-related niche differentiation may further reduce intraspecific competition.