User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-5950847-20130715182719

So according to the Japanese wiki, Loro and Ray Gougarf aren't male and female like Rathalos/Rathian or Kamu/Nono Orugaron, but rather Loro is a recessive gene variant that's more agressive than the standard Ray. That might explain why Loro is the one that allows for rage mode and leads the team attacks

On the other hand it makes you wonder how advanced science is in the Monster Hunter world that they know their genetics