title: Mammalian aging, metabolism, and ecology: evidence from the bats and marsupials.
abstract: This study compared trends in body size, life span, metabolic rate, and ecology of bats and marsupials with those from mammals generally, using a 580 species data base. The linear logarithmic relationship between mammalian body mass and maximum longevity, deleting bats and marsupials, is used as a standard against which to measure life spans of particular mammal groups. Bats have maximum life spans a minimum of 3 times those of nonflying eutherians--a trend resulting from neither low basal metabolic rate, the ability to enter torpor, nor large relative brain size. Marsupials live about 80% as long as nonflying eutherians despite averaging lower basal metabolic rates; similarly, there is no effect of heterothermy or relative brain size. These results directly conflict with predictions of both "rate of living" and brain-size mediated theories of aging. However, they are consistent with an evolutionary theory that posits exceptionally long life spans among mammals with reduced environmental vulnerability.
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University.
authors.forename: S N
authors.initials: SN
authors.lastname: Austad
authors.forename: K E
authors.initials: KE
authors.lastname: Fischer
mesh_terms: D000375:Aging / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001481:Basal Metabolism / Q000502:physiology; D001824:Body Constitution; D001831:Body Temperature; D002685:Chiroptera / Q000378:metabolism / Q000502:physiology*; D004463:Ecology; D004734:Energy Metabolism / Q000502:physiology; D006605:Hibernation / Q000502:physiology; D008136:Longevity; D008322:Mammals / Q000378:metabolism / Q000502:physiology*; D008394:Marsupialia / Q000378:metabolism / Q000502:physiology*