The influence of snow cover, elevation, and latitude on fur colour in the mountain hare

This study investigates the environmental factors, that influence the timing of winter fur change in the mountain hare (Lepus timidus). The transition from brown to white fur is a critical adaptive strategy that allows hares to remain camouflaged in snowy environments. Using data collected with camera traps from various elevations and latitudes, we analysed the influence of environmental factors, including snow presence, altitude, and latitude, on fur colour change. Our findings reveal that snow presence is the most significant determinant, with a strong correlation between snow cover and the transition to white fur. Latitude also significantly influences fur colour, likely reflecting the environmental gradients that vary with geographic location. In contrast, altitude did not have a significant effect on fur colour, nor did it interact with latitude in any meaningful way. However, seasonal altitudinal movements, driven by the availability of food and shelter, appear to influence the hare's habitat choice, with hares moving to lower elevations during winter to access food and higher elevations in summer. This seasonal behaviour may account for the lack of a direct correlation between altitude and fur colour. These results underscore the importance of snow cover and latitude as primary drivers of fur colour change, while altitude plays a secondary role. The findings highlight the need for conservation strategies that consider the potential impacts of climate change on snow cover dynamics, which could disrupt the synchronization between fur colour change and the environment, increasing hares' vulnerability to predation.