Quark number scaling of the measured elliptic
anisotropy parameter v2 can be a one of the
strong evidence for quark gluon plasma formation
in high energy heavy ion collisions. High pt
suppression (jet quenching) caused by energy-loss
of initially produced parton would be another
source of anisotropy especially at high pt.
Thermalization as well as suppression of heavy
quarks will give an additional proof of existance
of quark phase before hadronization. Non-photonic
electrons measured at RHIC energies are dominated
by heavy flavor decays especially at high pt.
Several experiments at RHIC has measured non-photonic
single electron and muon spectra as well as elliptic
anisotropy in order to look for a different behavior
of heavy quarks compared with light quarks.
Experimental measurements at RHIC are overviewed
and discussed.