In addition to genetics, environmental factors such as diet and exposure to sunlight can also affect the color of a fox's coat. For example, a diet rich in certain carotenoids (pigments found in plants and animals) can enhance the orange coloration of a fox's fur, while exposure to sunlight can cause the fur to fade over time.
Overall, the orange color of a fox's coat is a result of a combination of genetic and environmental factors that contribute to the production and distribution of pheomelanin in the fox's skin.