User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-1758220-20110713183743/@comment-969093-20110713192225

Rathalos and Rathian are pretty well adapted to almost any ecological system. The only ecological niches they're incapable of surviving in are the ones that present low temperatures such as the Snowy Mountains. Though, that is not entirely true as Deserts, in which they also dwell, temperatures can greatly drop to sub-zero levels in the evening.

Next to that, both of them are pretty high up in the food chain. Few monsters would actually dare or bother to fight/compete with them. We're talking about the larger monsters in general here, such as Diablos/Agnaktor/Uragaan/Deviljho and of course those who are above them.

Same story, pretty much, for Kelbi and Aptonoth, with the exception of their position within the food chain. They're herbivores that can live in balanced and hot climates, but not extreme heat. As long as there is flora they can pretty much survive anywhere.

Don't know about Diablos though.