  In scenarios with extra dimensions and TeV-scale quantum gravity, black holes
are expected to be produced in the collision of light particles at
center-of-mass energies above the fundamental Planck scale with small impact
parameters. Black hole production and evaporation may thus be studied in detail
at the Large Hadron Collider (LHC). But even before the LHC starts operating,
neutrino telescopes such as AMANDA/IceCube, ANTARES, Baikal, and RICE have an
opportunity to search for black hole signatures. Black hole production in the
scattering of ultrahigh energy cosmic neutrinos on nucleons in the ice or water
may initiate cascades and through-going muons with distinct characteristics
above the Standard Model rate. In this Letter, we investigate the sensitivity
of neutrino telescopes to black hole production and compare it to the one
expected at the Pierre Auger Observatory, an air shower array currently under
construction, and at the LHC. We find that, already with the currently
available data, AMANDA and RICE should be able to place sensible constraints in
black hole production parameter space, which are competitive with the present
ones from the air shower facilities Fly's Eye and AGASA. In the optimistic case
that a ultrahigh energy cosmic neutrino flux significantly higher than the one
expected from cosmic ray interactions with the cosmic microwave background
radiation is realized in nature, one even has discovery potential for black
holes at neutrino telescopes beyond the reach of LHC.
