A tiny freshwater hydra shows no measurable signs of aging, and when Daniel Martinez tracked three cohorts of them at Pomona College for four years the death rate never rose once — over that same stretch each animal had quietly replaced its entire body, cell by cell, at least 60 times

The freshwater polyp Hydra vulgaris shows no measurable signs of aging in laboratory colonies, and researchers have watched single animals regenerate from pinhead-sized fragments more than sixty times without cellular decline. A 2021 paper in Genome Biology and Evolution mapped how it does it. The post A tiny freshwater hydra shows no measurable signs of aging, and when Daniel Martinez tracked three cohorts of them at Pomona College for four years the death rate never rose once — over that same