May 14th, 2026
The work noted here might be taken as a companion piece to a recent paper on eusociality as a driver of the evolution of exceptional longevity in a wide variety of clades, not just mammals. Here, researchers take a broad look across mammalian species that exhibit a variety of different type of social organization, and find a correlation with species longevity. While thinking about this, one might also look at the evidence for mating strategies to drive the evolution of longevity; one might think that social organization has a large impact on mating strategy. At root, one might ask how all of these various parameters and their outcomes affect the trade-off between growth and maintenance in individuals; as a rule, species that mature faster can achieve reproductive success more reliably in an uncertain environment, but at the cost of a shorter life span and less opportunities to reproduce over time.
Extrinsic mortality, largely driven by predation, imposes strong selective pressures on ageing and longevity. Body size is perhaps the most important factor: larger mammals generally face fewer predators, allowing them to allocate more resources to maintenance and repair, thereby extending their lifespans. Comparative analyses of bats and marsupials similarly support reduced environmental vulnerability as a driver of longer lifespan. Furthermore, lifespan is correlated with other traits, including age at maturity and parental investment, consistent with the trade-off between energy allocation for reproduction and cellular repair. Increasingly, behavioural factors such as sociality are recognised for their impact on lifespan dynamics, adding another dimension to our understanding of longevity evolution.
