Two studies published this Thursday in the journal Science By uncovering scant evidence of aging among some cold-blooded species, he challenged an evolutionary theory that says aging or gradual physical decline is an inevitable fate. Scientists have discovered the secret of eternal youth: Being a turtle.

David Miller, a Penn State University researcher and author of one of the papers, told AFP that although there have been individual reports such as that of the Seychelles tortoise Jonathan, who turned 190 this year, these are considered anecdotal.

For their paper, Miller and colleagues gathered data from long-term field studies involving 107 populations of 77 species, including turtles, amphibians, snakes, crocodiles and tortoises.

They used a technique called “cue-recapture,” in which a certain number of individuals were first captured and tagged, and then the researchers followed them over the years to see if they were found again, to derive probabilistic mortality estimates.

They also collected data on how many years the animals lived after reaching sexual maturity and used statistical methods to generate aging rates.

The turtle is not immortal

“We found insignificant examples of aging,” said lead biologist and researcher Beth Reinke of Northeastern Illinois University.

“Insignificant aging or aging doesn’t mean they’re immortal,” he said. So there is a possibility of death, but this does not increase with age.

The study was funded by the National Institutes of Health, which is interested in learning more about aging in ectotherms, or cold-blooded species, and applying it to warm-blooded humans.

Ectotherms have a lower metabolism and age more slowly than endotherms, who internally generate their own heat and have higher metabolisms.

• Why did we humans lose our tails?

not metabolism

However, the authors of this new study found that metabolism does not play as central a role as previously thought.

“Although there are ectotherms that age slower and live longer than endotherms, there are also ectotherms that age faster and live shorter.”

The study also provided clues for future research.

By looking directly at a species’ average temperatures rather than its metabolic rate, the scientists found that warmer reptiles age faster, while the opposite is true for amphibians.

Animals with protective physical traits lived longer and aged more slowly than those without.

“A shell is important for aging because it makes a turtle really hard to eat and makes it live longer,” Miller said.

another study

A second study by a team from the University of Southern Denmark and other institutions applied similar methods to 52 turtle species in zoo populations and found that 75% showed negligible aging.

“Human health and longevity could benefit if some species do indeed survive aging, and if mechanistic studies can reveal how they do it,” scientists Steven Austad and Caleb Finch said in a commentary on these studies.

However, some species have noted that they do exhibit age-related diseases, even if they do not have increasing mortality rates over the years.

“Now he is blind, he has lost his sense of smell and has to be fed by hand,” said Jonathan the Tortoise, showing that the ravages of time will come for all.