Invisible Snow Fox!

If you take my word for it,  you may just make out the shadowy form of a (pure white) arctic snow fox leaping, upper right, in between the buildings.  As soon as he saw us he took off.  I snapped this as fast as I could but the light was dim.  I can just barely make out his outline.  This was the only time we spotted him - he was going through people's trash in town.  His head is to the rt, rear legs extended to the left.