Interestingly, the team observed negligible aging in at least one species in each of the ectotherm groups, including in frogs and toads, crocodilians and turtles.

“It sounds dramatic to say that they don’t age at all, but basically their likelihood of dying does not change with age once they’re past reproduction,” said Reinke.

Miller added, “Negligible aging means that if an animal’s chance of dying in a year is 1% at age 10, if it is alive at 100 years, its chance of dying is still 1% (see * below). By contrast, in adult females in the U.S., the risk of dying in a year is about 1 in 2,500 at age 10, and 1 in 24 at age 80. When a species exhibits negligible senescence (deterioration), aging just doesn’t happen.”

Reinke noted that the team’s novel study was only possible because of the contributions of a large number of collaborators from across the world studying a wide variety of species.

“Being able to bring these authors together who have all done years and years of work studying their individual species is what made it possible for us to get these more reliable estimates of aging rate and longevity that are based on population data instead of just individual animals,” she said.

Bronikowski added, “Understanding the comparative landscape of aging across animals can reveal flexible traits that may prove worthy targets for biomedical study related to human aging.”

For a list of authors and their affiliations, please see the published manuscript in Science.

The National Institutes of Health supported this research.

*According to the U.S. Social Security Actuarial Life Table, accessed June 1, 2022.