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The evolutionary theory of aging predicts that species will experience delayed senescence and increased longevity when rates of extrinsic mortality are reduced, It has long been recognized that birds and bats are characterized by lower rates of extrinsic mortality and greater longevities than nonvolant endotherms, presumably because flight reduces exposure to terrestrial predators, disease, and environmental hazards. Like flight, arboreality may act to reduce extrinsic mortality, delay senescence, and increase longevity and has been suggested as an explanation for the long lifespans of primates. However, this hypothesis has yet to be tested in mammals in general. We analyze a large dataset of mammalian longevity records to test whether arboreal mammals are characterized by greater longevities than terrestrial mammals. Here, we show that arboreal mammals are longer lived than terrestrial mammals at common body sizes, independent of phylogeny. Subclade analyses demonstrate that this trend holds true in nearly every mammalian subgroup, with two notable exceptions-metatherians (marsupials) and euarchontans (primates and their close relatives). These subgroups are unique in that each has experienced a long and persistent arboreal evolutionary history, with subsequent transitions to terrestriality occurring multiple times within each group. In all other clades examined, terrestriality appears to be the primitive condition, anspedes that become arboreal tend to experience increased longevity, often independently in multiple lineages within each dade. Adoption of an arboreal lifestyle may have allowed for increased longevity in these lineages and in primates in general. Overall, these results confirm the fundamental predictions of the evolutionary theory of aging. [ABSTRACT FROM AUTHOR]

Across mammals, encephalization and longevity show a strong correlation. It is not clear, however, whether these traits evolved in a correlated fashion within mammalian orders, or when they do, whether one trait drives changes in the other. Here, we compared independent and correlated evolutionary models to identify instances of correlated evolution within six mammalian orders. In cases of correlated evolution, we subsequently examined transition patterns between small/large relative brain size and short/long lifespan. In four mammalian orders, these traits evolved independently. This may reflect constraints related to energy allocation, predation avoidance tactics, and reproductive strategies. Within both primates and rodents, and their parent clade Euarchontoglires, we found evidence for correlated evolution. In primates, transition patterns suggest relatively larger brains likely facilitated the evolution of long lifespans. Because larger brains prolong development and reduce fertility rates, they may be compensated for with longer lifespans. Furthermore, encephalization may enable cognitively‐complex strategies that reduce extrinsic mortality. Rodents show an inverse pattern of correlated evolution, whereby long lifespans appear to have facilitated the evolution of relatively larger brains. This may be because longer lived organisms have more to gain from investment in encephalization. Together, our results provide evidence for the correlated evolution of encephalization and longevity, but only in some mammalian orders. [ABSTRACT FROM AUTHOR]