Reproduction, ageing, and longevity in two species of laboratory rodents with different life histories

Social subterranean rodents of the Bathyergidae family are known to have extended longevity and some signs of negligible senescence, although the manifestation of these traits depends on the reproductive status of individuals. Such enormous life history peculiarities are usually explained by the specificity of a subterranean way of life. If so, all subterranean rodents, regardless of their taxonomic position, are expected to have higher maximum lifespans and shorter senescence periods than the related above-ground species. In this study we compared the mortality rates and age-related reproductive activity and physical conditions in two sympatric rodents of the Cricetidae family: subterranean mole voles and above-ground dwarf hamsters. Mole voles have a maximum lifespan that is as high as two times the maximum lifespan of the dwarf hamsters; however, only a few mole voles outlasted the maximum lifespan of dwarf hamsters. Dwarf hamsters were generally more fecund than mole voles, which manifests both in a higher number of litters and larger litter sizes. Neither species demonstrated a significant age-related decline in litter size or muscle strength, although there were negative trends for dwarf hamsters. We conclude that some evidence of extended longevity and slow ageing do occur in mole voles, but due to the relatively short "subterranean" phylogenetic history of the species, this evidence is not as pronounced as in the social species of Bathyergidae family.