During the winter, this species of fox has white fur, but in the summer, it has brown fur. What environmental change may have lead to this fox's fur color?

Seasonal changes in snow cover can trigger a change in the fox’s coat color. White fur blends into snowy winter surroundings, while brown fur provides camouflage when the snow melts and the ground is exposed. The environmental change is snow cover, not a change in the Sun’s brightness or a volcanic eruption.

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