>>2847803 (OP)
Just thumbing through the Wikipedia article real quick, my best guess is hypothermia + panic/lost person behavior + animals got to the soft tissues.
Some key factors, looks like they were up against extreme temperatures that they maybe weren't anticipating, there was a ~60 day delay between their disappearance, and they were at very low elevation so they didn't experience any altitude-related issues.
t. Still to do Wilderness Medicine stuff sometimes