I was on a walk down the Macclesfield Canal near Gurnett with the family and some friends yesterday. We saw a black ferret like animal doggy paddling down the side of the canal. It ran along the side of the canal for a bit too. It was very dark/black with very few markings/colourings and according to Wikipedia was about the right size/colour for a North American Mink. Combined with the steam engine we saw it was a pretty exciting little stroll 
I'll add piccies when my mate forwards them. Maybe we can have an "animals you were surprised to see" thread.
the old ones are the best.
