The drummer in a band
 

Is the drummer in a band supposed to write all their own beats for a song. I have noticed that in most bands, the drummer doesn't do any song writing. However, I have heard that the drummer will still write all the beats, despite not getting any credit for song writing.

he probably just goes into the studio with nothing in plan, hears the songs, and jsut makes up beats on spot.

Yeah they mostly just go in and start making something up right then but sometime's they won't, it all depends.