Complex sentence: In size and proportions, the ferret is similar to the European polecat, to the point that dark coloured ferrets are almost indistinguishable from their wild cousins, though the ferret's skull has a smaller cranial volume, and has a narrower postorbital constriction.
Split into simpler sentences: In size and proportions, the ferret is similar to the European polecat, to the point that dark coloured ferrets are almost indistinguishable from polecats. The ferret's skull has a smaller cranial volume than the polecat's, and has a narrower postorbital constriction.