This dataset was used in a comparative analysis of longevity in bats. Bats live longer than similar-sized mammals, but the number of lineages that have independently evolved extreme longevity has not previously been determined. Here we reconstruct the evolution of size-corrected longevity on a recent phylogeny and find that at least four lineages of bats have lifespans more than four-fold those of similar-sized placental mammals with the ancestral bat projected to live 2.5 times as long. We then use an information theoretic approach to evaluate a series of phylogenetic generalized least squares (PGLS) models containing up to eight variables hypothesized to influence extrinsic mortality. The PLGS analyses reveal that body mass and hibernation predict longevity. Among hibernators, longevity is predicted by median latitude of the species range, while cave roosting and lack of sexual dimorphism predict longevity among nonhibernators. The importance of torpor in extending lifespan is further supported by the one lineage with extreme longevity that does not hibernate but does exhibit flexible thermoregulation, the common vampire bat. We propose a number of potential mechanisms that may enable bats to live so long, and suggest that the ability to tolerate a wide range of body temperatures could be particularly important for surviving viral or other pathogen infections.