User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-1758220-20111222010738/@comment-4674269-20111223043232

Correct me if I'm wrong but the Moga area is an anarchipelego. Possibly Raths evolved larger wings due to the increased need to travel from island to island in order to hunt. Not to mention the difficulties in other areas such as all the water in the Flooded Forest,  hard to reach valleys in the Mountain Stream, and The Great Desert... is self explanatory. The stockier legs might exist in order to support the weight of the larger wings when on the ground. Another reason could be because of all the other large predators introduced in the 3rd gen. Back in Minegard Raths were the top dogs, but here they have to compete with sea dwelling Lagiacrus along with Jinouga, Bracchidios, Agnaktor,and Deviljho on land (or lava in Agnaktor's case) where the sky would be their only advantage.