Nature uncovers the secret lives of creatures that never grow old:
A comparison of standardized demographic patterns across 46 species, published today in Nature, suggests that the vast diversity of ‘ageing strategies’ among them challenges the notion that evolution inevitably leads to senescence, or deterioration of mortality and fertility, with age, says Owen Jones, a biologist at the University of Southern Denmark in Odense, who led the study.
“By taking a grand view and doing a survey across species, we found plenty of violations of this underpinning theory,” says Jones.
To compare fertility and mortality patterns, the authors assembled published life-history data sets for 11 mammals, 12 other vertebrates, 10 invertebrates, 12 vascular plants and a green alga, and standardized the trajectories — dividing mortality rates at each point in the lifespan by the average mortality rate.
They found no association between the length of life and the degree of senescence. Of the 24 species showing the most abrupt increase in mortality with age, 11 had relatively long lifespans and 13 had relatively short lifespans. A similar split in lifespan occurred in the species that had a less abrupt increase in mortality.