  We calculate analytically low frequency quasi-normal modes of gravitational
perturbations of AdS Schwarzschild black holes in $d$ dimensions. We arrive at
analytic expressions which are in agreement with their counterparts from
linearized hydrodynamics in $S^{d-2}\times \mathbb{R}$, in accordance with the
AdS/CFT correspondence. Our results are also in good agreement with results of
numerical calculations.
