Is it possible to attend the US Naval Academy and then join the Marines after college instead of the Navy?

I thought if you attended the Navy, Army, or Air Force academy you had to join their service for 8 years after you got done with college. I Was wondering if it is possible to join the Marines afterwards instead of the Navy if you went to Navy. I was wondering this because I was watching Survivor and one of the contestants was a Marine in the Iraq War. However, his Bio on the survivor website says that he played college football at the US Naval Academy. Is this possible? Thank you for you answers.