User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-6050823-20130801130351/@comment-5460283-20130801135903

I think all Rathalos species were trained to be gaurdians by the ancient inhabitants of the tower. And somehow they rebelled causing the inhabitants to flee. Or Elder Dragons came and over powered the inhabitants and then many generations later when the ancients were forgotten the Raths have turned hostile towards humans...

So i think all of the rath species are not naturally created rather specific training methods or ranks used by the ancients on them.(E.G. Red Los was not trained as much as Tenshou Los)