User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-4212769-20120601200745/@comment-4212769-20120604153706

Only to say it: Black Diablos is confirmed being the female form in the mating season but is also referred as own subspecies. So why can't Nargacuga Subspecies be the same as that just not in mating season but always? Just a question: Was the "Black Diablos is female" theory already confirmed from the first game? I don't think so because it wouldn't be discussed here anytime when it's already confirmed. So I think it can still change.

And I want to give a theory why Narga Sub can K.O. a monster with his spikes and Nargacuga not based on my theory above:

Both have glands that produce this fluid for stunning but in the normal Narga the gland doesn't get activated because of the lack of hormones that would do so. I would say Green Nargacuga is the male form. Through the male sexual hormones (testosterone) the gland gets the order to produce the fluid. That's why Nargacuga hasn't got the K.O. effect.