  The exceptional group $G_2$ has two maximal parabolic subgroups $P_{long}$,
$P_{short}$ corresponding to the so-called long root and short root. In this
paper, the second author introduces two zeta functions associated to
$(G_2,P_{long})$ and $(G_2,P_{short})$ respectively, and the first author
proves that these zetas satisfy the Riemann Hypothesis.
