What is a practical reason shepherds selected for the Great Pyrenees' uniform white coat?

Answer

It allowed easy distinction from dark predators like wolves or bears in dim light.

The bright white coat was a human-driven trait selected so shepherds could easily identify their guardian dog versus dark-colored predators during patrols at dawn or dusk, preventing accidental shooting.

What is a practical reason shepherds selected for the Great Pyrenees' uniform white coat?
ancestrywolfdog breedGreat Pyrenees