I enjoy the fact the Royal Ludroth actually makes that sound and surprised me so much when I first encountered it. To the point it took me minutes for it to register that indeed it came from THAT monster.
*sigh's* i wish Tigrex and Brute Tigrex, and Amastu where in Monster Hunter 3 Ultimate.. :( MY Theory : i think Dire Miralis replaced the Akantor in MH3U even if Akantor was planned in the game..