  Tunneling spectra are reported for Bi_{2}Sr_{2}CaCu_{2}O_{8+\delta} (Bi-2212)
over a wide doping range using superconductor-insulator-superconductor (SIS)
break junctions. The energy gap inferred from the tunneling data displays a
remarkable monotonic dependence on doping, increasing to very large values in
the underdoped region even as T_c decreases. This leads to unphysically large
values of the strong coupling ratio ($\sim$20). The tunneling spectra are
qualitatively similar over the entire doping range even though the gap
parameter, $\Delta$, changes from 12 meV to 60 meV. Each spectrum exhibits dip
and hump features at high bias with characteristic energies that scale with the
superconducting gap. Tunneling spectra of near optimally-doped
Tl_{2}Ba_{2}CuO_{6+\delta} (Tl-2201) also display a weak dip feature in
superconductor-insulator-normal metal (SIN) junctions. Generated SIS spectra of
Tl-2201 are compared with measured spectra on Bi-2212 and it is concluded that
the dip and hump features are generic to high temperature superconductors.
