Aging, as defined in terms of the slope of the probability of death versus
time (hazard curve), is a generic phenomenon observed in nearly all complex
systems. Theoretical models of aging predict hazard curves that monotonically
increase in time, in discrepancy with the peculiar ups and downs observed in
empirically. Here we introduce the concept of co-aging, where the demographic
trajectories of multiple cohorts couple together, and show that co-aging
dynamics can account for the anomalous hazard curves exhibited by some species.
In our model, multiple interdependency networks inflict damage on one other
proportional to their number of functional nodes. We then fit our model
predictions to three datasets describing (1) co-aging worm-pathogen populations
(2) competing tree species. Lastly, we gather the mortality statistics of (3)
machine-against-machine chess games to demonstrate that co-aging dynamics is
not exclusive to biological systems