Very old reptiles give clues to longevity in humans – Consumer Health News

FRIDAY, June 24, 2022 (HealthDay News) — Historically, little has been recorded about the aging of amphibians and reptiles, unless they live in a zoo.

Now, a team of international researchers has changed that in a study that has traveled the world.

The team of 114 scientists, led by researchers from Penn State and Northeastern Illinois University, conducted the most comprehensive study to date of aging and longevity in “cold-blooded” animals. Investigators collected data in the wild from 107 populations of 77 species of reptiles and amphibians, learning new details about how these creatures age in the process.

“There is anecdotal evidence that some reptiles and amphibians age slowly and have long lifespans, but so far no one has really studied this on a large scale on many species in the wild,” said the study’s lead author, David Miller, associate professor of wildlife population. ecology at Penn State, in University Park, Pennsylvania.

“If we can understand what causes certain animals to age more slowly, we can better understand aging in humans, and we can also inform conservation strategies for reptiles and amphibians, many of which are threatened or endangered. disappearance,” Miller said in a Penn State News. Release.

The effort paid off: For the first time, researchers have documented that turtles, crocodilians and salamanders have particularly slow rates of aging and extended lifespans for their size.

And, in at least one species from every group of cold-blooded animals, including frogs, toads, crocodilians, and turtles, the animals did not age biologically at all.

“It sounds dramatic to say they don’t age at all, but fundamentally their likelihood of dying doesn’t change with age once they’ve outgrown reproduction,” said study first author Beth Reinke, assistant professor of biology at Northeastern Illinois University. , in Chicago.

“Negligible aging means that if an animal’s risk of dying in a year is 1% at age 10, if it is alive at 100 years old, its risk of dying is still 1%,” she explained. “In contrast, among adult females in the United States, the risk of dying in one year is approximately 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.”

The aim of the study was to analyze the variations in aging and longevity of cold-blooded animals in the wild compared to the aging of warm-blooded animals. The researchers also aimed to explore previous hypotheses related to aging, including the regulation of body temperature and the presence or absence of protective physical traits.

An earlier hypothesis suggested that cold-blooded animals age more slowly than warm-blooded animals due to the way they regulate their body temperature and metabolism.

“People tend to think, for example, that mice age quickly because they have a high metabolism, while turtles age slowly because they have a low metabolism,” Miller said.

Instead, Miller’s team found that the aging rates and lifespans of cold-blooded animals were both much higher and lower than known aging rates for warm-blooded animals of similar size. This suggests that how an animal regulates its temperature does not determine its rate of aging.

“We did not find support for the idea that a lower metabolic rate means [cold-blooded animals] age more slowly,” Miller said. “This relationship was only true for turtles, suggesting that turtles are unique among [cold-blooded animals].”

Another hypothesis, known as the protective phenotypes hypothesis, suggests that animals with protective traits such as armor, spines, shells, or venom age more slowly.

The team documented that these traits appear to allow animals to age more slowly or live much longer for their size.

“It could be that their altered morphology with hard shells provides protection and contributed to the evolution of their life histories, including negligible aging – or lack of demographic aging – and exceptional longevity,” said the co-lead author of the study, Anne Bronikowski, professor. of Integrative Biology at Michigan State.

The results of the study were published on June 23 in the journal Science.

More information

The US National Institute on Aging has more on another study on aging, this one in companion dogs.

SOURCE: Penn State, press release, June 23, 2022

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