Conversation so far:
why are arctic foxes white in the winter
A pigment called melanin, absent in white fur, gives the fox its brown summer coat.
why do arctic foxes turn white
White fur not only provides camouflage in winter but adds warmth. The hair shafts of white fur are hollow, trapping warm air from the animal's body heat.

Question: how much do the foxes eat
Self-contained rewrite: how much do arctic foxes eat