How do you unlock the monster hunter levels in Metal Gear Solid peace walker

To unlock the monster hunter levels you first have to complete main ops 1 through 15 then listen to all of Chico's tapes, then play extra ops 29 or 35 as snake, When it start out backtrack to the coastal area and look for a cat on a boat named Treya, he is next to the dock, go close to him and a cutscene will activate after it done the mission will end and the monster hunter will become available.