sorry if this has already been addressed

Just in the process of levelling my first werewolf (for quite some time) choose Pack leader which of course now comes with the 2 dire wolves

I quite like the fact that my wolves keep changing colour (brown/white/black), but i am curious whether it is simply a cosmetic thing; or is their colour an indication of their strength dictated by the level of your werewolf skills (some of the skills still have 1 or 2 levels to go before they are maxed)

thnx in advance