A new model explains why lifespans vary so much
Why do humans live for decades while other mammals age out in a few years? A new mathematical model offers the first unified answer to that question.
Biologists have studied aging for centuries, but comparing aging patterns across species remained methodologically difficult. Survival curves look very different in mice compared to humans or naked mole-rats. Researchers publishing in the journal Nature Aging developed a mathematical framework that converts survival data into a common measure: the rate at which cells accumulate damage.
Two aging regimes, one model
The model revealed two clear regimes. In some species, the probability of death rises quickly after reproductive age, with damage accumulating at an accelerating rate. In others, including humans, damage accumulates more gradually over a much longer period. The study shows that this distinction is quantifiable and consistently appears across data from diverse species.
The framework offers a way to better translate findings from model organisms, such as mice or fruit flies, to human biology. Until now, such direct comparisons were difficult because the timescales differ so greatly. With this model, researchers can express the relative aging rate of a species in comparable units.
Useful for longevity research
The researchers argue that their model provides a quantitative basis for asking why and how aging patterns diverge across species. That is relevant for longevity research: if an intervention slows damage accumulation in mice, this model could help estimate the expected magnitude of that effect in humans. The researchers are themselves cautious: the model is a mathematical description of survival patterns, not a direct measurement of biological mechanisms.