etymology online has this for hunker:

"to squat, crouch," 1720, Scottish, probably from O.N. huka "to crouch," hoka, hokra "to crawl." Hunker down, Southern U.S. dialectal phrase, popularized c.1965, from northern British hunker "haunch."


but if you want lots of speculation about the phrase,
google:
"hunker+down" +origin

Last edited by tsuwm; 11/02/2005 7:09 PM.