The Collaborative International Dictionary of English v.0.48:

Hunkers \Hun"kers\, n. pl. [See Hunker.]
   In the phrase on one's hunkers, in a squatting or crouching
   position; haunches. [Scot. & Local, U. S.]

         Sit on your hunkers -- and pray for the bridge.
                                                  --Kipling.
   [Webster 1913 Suppl.]