Senescence in ectothermic vertebrates: Peaks and valleys in the landscape of reptilian aging

Background/Question/Methods

Specific taxa within ectothermic reptiles have been highlighted as
slow-aging relative to mammalian and avian taxa of similar body size. These
observations have often relied on maximum life span, indeterminate growth,
and size-related fecundity. These data are valuable and difficult to obtain, yet
are indirect in their assessment of demographic patterns across the life
span. Here we report analyses of long-term individual-based studies, spanning
30+ years of fieldwork on snakes and turtles, to understand the patterns of reproductive and mortality
senescence.

Results/Conclusions

We find measurable senescence along both the reproduction and mortality axes, but the patterns contrast with mammalian and avian senescence. We interpret our findings in the context of proposed mechanisms for the evolution and ecology of aging.