An international team of 114 scientists reports the most comprehensive study of aging and longevity to date of reptiles and amphibians worldwide. Among their many findings, they document for the first time that turtles, crocodilians and salamanders have particularly low aging rates and extended lifespans for their sizes. The team also finds that protective phenotypes, such as the hard shells of most turtle species, contribute to slower aging, and in some cases even ‘negligible aging’ — or lack of biological aging.