User blog comment:Lord Loss/Discussion of the Week: Brute Wyverns/@comment-4697976-20130115014833/@comment-4212769-20130117183526

It's not sure if it is a true subspecies it could be a mating season form too (although the color may not be very useful as they don't see...). Maybe with the hormones they get a more "attractive" smell but with that also the color changes.