Scaling life as an interspecies hallmark of aging

Across species, the “pace of life”—encompassing develop-ment, reproduction, and senescence—varies widely, yet the molecular mechanisms that regulate these interspe-cies trajectories of aging remain elusive. Even among ver-tebrates, a 1000-fold difference in life span is observed between species, ranging from several months in the turquoise killifish to half a millennium in the Greenland shark. As a relatively “young” area of investigation, aging research lacks the unifying conceptual frameworks that anchor more established disciplines, such as neurosci-ence. Therefore, current theories, which in some cases provide contradicting predictions, rely heavily on experimental data to mature. These contradictions not only define key outstanding questions but also illuminate fer-tile ground for transformative research.