Alexandra: The provenance of this creature is debatable, and Wikipedia is not the ultimate authority. And if you trust it, then you must also question the origin of the domestic ferret, since Wikipedia itself says that it is somewhat in question. In general (no absolutes here), weasels are longer and slimmer of body, while this "siberian weasel" appears to be stockier and shorter, more resembling a polecat (which is itself still not definitely established as a separate species). I was only making a guess, but given the fact that the origin of the domestic ferret is till very much a matter of debate, I would not give much weight to the fact that Wikipedia calls it a "weasel". [Posted in FML 7503]