Many organisms have a pattern of temporal change and senescence that is reproducible and predictable for the species and gender — clearly with a huge genetic component. For example, the longevity of rats is 3.8 years while their ‘cousins’ the mole-rats live up to 30 years. These timings are probably optimized to fit with the ecology patterns of the species — predation, litter size, environmental variation, food abundance, etc.