Survival of Laboratory-Reared Pocket Mice, Perognathus longimembris

The relationship of death and age in pocket mice (Perognathus longimembris) was determined in a cohort of 216 animals derived from breeding experiments with field trapped animals. A maximum life span of 8.3 years was found. The pattern of mortality as revealed by a comparison of its qx curve with other rodents seems to be distinctly different. There is a prolongation of moderate mortality at a time when mortality rates of other mammals are tending toward a logarithmic increase. The ramifications of torpor on longevity and ecological strategy are discussed.