User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-5043481-20120924195637/@comment-5460283-20120925130441

Actually the definition of "Tundra" is a cold open plain with little trees and a permafrost on the ground. In other words the ground is frozen to 0.5-3 inches. That means the ground is extremely hard.

I think the barroth sub's crest is bigger to break up the ground more easily because the force of the crest hitting the ground would break up the outer permafrost to make digging easier.