That dark brown ferret is most likely a Mink. I've been on a couple lost ferret calls that turned out to be a mink. My brother thought he found a lost ferret and held out his had to this seemingly tame animal and it bite him. It was a Mink and he ended up getting rabbi shots. It the ferret is completely dark brown with maybe a small with patch under his chin it is a mink. The only solid color ferret I know of is white. All other ferrets are more than one color or at least has at least two different shades (head and legs one color and body another) Mike [Posted in FML 7111]