The silver mitt (black mit and actually most ferrets) are lighter in their
winter coats than their summer coats.  One of my lightest jills is virtually
a DEW in the winter but has quite a bit of black in the summer.  Several of
my Sables are drastically darker in the summer than the winter.
 
bill and diane killian
zen and the art of ferrets
[Posted in FML issue 1218]