We will present STAR's measurements of the elliptic flow parameter v2 for Lambda and K short in Au+Au collisions at both 62.4 and 200 GeV. The high statistics 200 GeV measurements have been extended up to transverse momentum pt ~ 7 GeV/c. At low pt, the values of Lambda and K short v2 are consistent with the results predicted by hydrodynamic models. At a given pt, the heavier the hadron mass, the smaller the value of v2. In the intermediate pt region (pt from 2-5 GeV/c), we observe departures from the hydro trend. There, the values of v2 are scaled by the hadron type: the v2 of baryons is higher than that of mesons. The new trend seems to follow the so-called number of constituent quark (NCQ) scaling. Two important consequences arise from these observations:
(i) 'collective flow' has developed prior to hadronization - partonic collectivity at RHIC; (ii) prior to hadronization, partons are flowing
in a volume that is much bigger than that of a nucleon.