  In this short note we derive a formula which describes the dependence of the
mass of a hadron which contains a single heavy quark on the temperature of the
heat bath. It takes a simple scaling form with the exponent which is different
than in the case of the light hadrons. The derivation is based on dimensional
arguments within the framework of the bag model paradigm. The simple
realization of this scenario is presented for the MIT bag model. The mass
splitting between pseudoscalar and vector mesons ($D, D^\ast$ or $B, B^\ast$)
as a function of temeperature is presented.
