  We discuss the merger process of binary black holes with Hawking radiation
taken into account. Besides the redshifted radiation to infinity, binary black
holes can exchange radiation between themselves, which is first redshifted and
then blueshifted when it propagates from one hole to the other. The exchange
rate should be large when the temperature-divergent horizons are penetrating
each other to form a single horizon with unique temperature. This will cause
non-negligible mass and angular momentum transfer between the black holes
during the merging process of the horizons. We further argue in the large mass
ratio limit that the light hole whose local evaporation is enhanced by the
competing redshift-blueshift effects will probably evaporate or decay
completely before reaching the the horizon of the heavy one. We also discuss
the possibility of testing Hawking radiation and even exploring the information
loss puzzle in gravitational wave observations.
