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For mammals like humans, aging is inevitable. No matter how many vitamins we take, over time the skin sags, the bones soften and the joints harden. However, tortoises and tortoises age more gracefully. Despite their wrinkled skin and toothless gums, Galapagos giant tortoises seems unaffected by the ravages of aging. Some show little sign of slowing down as they enter their 100s.
To determine what drives these ageless wonders, two groups of researchers examined turtles, tortoises, and their ectothermic, or cold-blooded siblings, in a pair of studies published Thursday in the journal Science. Previous research on aging has largely revolved around warm-blooded animals such as mammals and birds. But like ectotherms the fish, reptiles and amphibians dominate the longevity record books. For example, the so-called salamander they die It has been crawling in underground caves for about a century. Giant tortoises can live twice as long – earlier this year a Seychelles tortoise named Jonathan celebrated its 190th birthday.
Inside one of the new worksThe researchers compiled datasets on 77 wild reptile and amphibian species. Komodo dragons, garter snakes and tree frogs. The team used decades of monitoring data to analyze traits such as metabolism to determine their effects on aging and longevity.
“We had these amazing datasets to tackle the questions of aging in a way that hasn’t been done before,” said Beth Reinke, an evolutionary biologist at Northeastern Illinois University and author of the new study. “Getting to the heart of how aging develops can only be done with this broad taxonomic approach.”
Living this long requires a gentle aging curve. After most animals reach sexual maturity, most of their energies are devoted to reproduction at the expense of repairing aging tissue. This physical deterioration or aging often results in an increased risk of death as older animals become susceptible to predators or diseases. But a few cold-blooded animals experience little aging as they age.
One theory is that cold-blooded animals are better equipped to manage the wear and tear of aging, as endothermic or warm-blooded animals rely on the environment to calibrate their body temperature rather than their energy-consuming metabolism. However, Dr. What Reinke and colleagues found was more complex. They discovered that some ectotherms age much faster than similarly sized endotherms, while others age much more slowly. Aging rates were scattered for lizards and snakes, but considerably lower for some crocodiles, salamanders and salamanders. the mysterious tuatara. However, the only group that did not age at all were tortoises and tortoises.
this other new work further deepened the aging of these timeless turtles. Researchers studied age-related decline in 52 captive turtle and tortoise species in zoos and aquariums. They found that 75 percent of the species, including the Aldabra giant tortoises and pancake turtles, exhibited low or negligible aging. A few, such as the Greek tortoises and black marsh turtles, have even exhibited negative aging rates, meaning the risk of death decreases as they age. About 80 percent had slower aging rates than modern humans.
That turtles are the anti-aging standard makes sense given their slow metabolism. The researchers also attributed their robust shells to longer lifespans. While herbivorous turtles and tortoises spend their lives eating vegetables (well, mostly), comfortable suits of armor offer protection even to gray-haired geeks.
These lethargic aging rates are not surprising considering the pampered lives of captive turtles. But unlike humans who age regardless of cryogenic preservation fantasy, captive turtles provide evidence that ideal environments in zoos can slow aging because the reptiles rest at ideal temperatures and enjoy a balanced diet of fruits and greens.
“We compared populations in zoos with wild populations and found that those under protected conditions can stop aging,” said Rita da Silva, a population biologist at the University of Southern Denmark and author of the turtle study. “Our environment for humans continues to get better and better, but we still can’t stop aging.”
According to Caleb Finch, a gerontologist who studies aging in humans at the University of Southern California, long-lived tortoises and tortoises do not have eternal youth, while the risk of death has remained stable for decades. Like older people, tortoises and tortoises eventually lose sight and hearts.
Not involved in the new studies, Dr. “Some get cataracts and weaken to the point where they need to be hand fed,” Finch said. “They can’t survive in the real world, so there’s no doubt they’re getting old.”
While these clumsy reptiles may not outlive death, they may have the insights to extend longevity and reduce age-related decline.
Dr. “If we continue to study the evolution of aging in turtles, at some point we will find a clear link between turtles and human health and aging,” said da Silva.
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