Comparative aging and life histories in mammals.

A comparative assessment of aging and longevity in mammals has four uses in aging research. These are: (1) hypothesis formulation and evaluation, (2) investigating the generality of putative aging mechanisms, (3) isolating key physiological factors influencing aging rate, and (4) allowing the most appropriate choice of animal models for particular research questions. The first use requires detailed information on a wide variety of species, and I will examine general patterns of aging in a sample of over 600 species of mammals. The second use requires the selection of several models as distantly related to one another as feasible. The third use is best served by evaluating species or populations as closely related to one another as possible, assuming that they differ substantially in aging rate. The fourth use requires a logic of animal model selection, as well detailed information about a wide range of species. Specific examples of each use will be given.