Department of Anthropology, University of Illinois, Urbana, IL 61801, USA.
Proc Natl Acad Sci U S A. 2010 Mar 9;107(10):4635-9. doi: 10.1073/pnas.0911439107. Epub 2010 Feb 22.
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, and species that become arboreal tend to experience increased longevity, often independently in multiple lineages within each clade. 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.
衰老的进化理论预测，当外在死亡率降低时，物种将经历衰老延迟和寿命延长。长期以来，人们一直认为鸟类和蝙蝠的外在死亡率较低，寿命较长，这可能是因为飞行减少了它们暴露在陆地捕食者、疾病和环境危害中的机会。与飞行类似，树栖生活方式可能会降低外在死亡率、延迟衰老并延长寿命，并被认为是灵长类动物长寿的原因之一。然而，这一假说尚未在哺乳动物中得到普遍验证。我们分析了大量哺乳动物寿命记录数据集，以检验树栖哺乳动物是否比陆地哺乳动物寿命更长。在这里，我们表明，在常见的体型下，树栖哺乳动物比陆地哺乳动物寿命更长，这与系统发育无关。亚群分析表明，这种趋势在几乎每一个哺乳动物亚群中都是真实的，只有两个显著的例外——有袋类动物（有袋目动物）和真兽亚纲（灵长目动物及其近亲）。这些亚群的独特之处在于，每个亚群都经历了漫长而持久的树栖进化历史，随后在每个群体中多次发生向陆地的转变。在所有其他被检查的进化枝中，陆地生活方式似乎是原始的条件，而变成树栖的物种往往寿命更长，通常在每个进化枝中的多个谱系中独立发生。总的来说，这些结果证实了衰老的进化理论的基本预测。
