Genomic data from samples that originate from different time periods (heterochronous samples) provide a unique opportunity to directly examine temporal changes in genome-wide diversity. Moreover, genomic data from different points in time can also be used to infer genome-wide mutation rates, which in turn can be used to assess the timing of demographic changes and population divergence events. The aim of this presentation is to showcase how such analyses can be done, using data from woolly mammoth and wolf as examples.