The disintegration of heavy nuclei at various excitation energies has been investigated on the basis of statistical models. For the fission channels at low energies, we obtain approximate interpolating formulas for masses of fission fragments from the analysis of experimental data. In particular, they describe the transition from symmetric to asymmetric fission. The sequential evaporation from the excited compound nucleus and fission fragments is also taken into account. We show the evolution of mass distributions from low to high excitation energies, and demonstrate a transition to multifragmentation channels at high energies. © Società Italiana di Fisica/Springer-Verlag 2013.