At 190 years of age, the Seychelles giant tortoise recently made headlines for being “the world’s oldest living animal.” Although, rare evidence such as this exists that some species of tortoises and other pets – or ‘cold-blooded’ animals – live longer, the evidence is stained and is more focused on wildlife living or in the wild. . Now, an international team of 114 scientists, led by Penn State and Northeastern Illinois University, reports on the most comprehensive study of aging and longevity so far that includes data collected from wild communities in 107 species of 77 reptiles and aquatic animals worldwide.
Among their many findings, reported today (June 23) in the journal Science, researchers first wrote that tortoises, crocodiles, and salamanders have relatively low aging rates and a longer lifespan of their size. The team also found that protective phenotypes, such as the hard shells of many tortoise species, contribute to slow aging, and in some cases even ‘careless aging’ – or the lack of biological aging.
“There is incredible evidence that some reptiles and amphibians are slowly growing and living longer, but so far no one has been able to read this to the full extent of all wildlife species,” said David Miller, senior author and associate professor of wildlife, Penn State. “If we can understand what allows other animals to grow slowly, we can better understand human aging, and we can also introduce conservation techniques for reptiles and aquatic animals, many of which are threatened or endangered.”
In their study, researchers used phylogenetic comparisons – which allow for the study of evolution — marking and retrieving data – when animals are captured, tagged, released back into the wild and seen. Their aim was to analyze the fluctuations of ectotherm aging and longevity in the wild compared to endothermes (warm-blooded animals) and to assess previous preconceived notions – including how to regulate body temperature and the presence or absence of protective features. Miller explained the ‘mode hypothesis ” Heaters’ suggest that ectotherms – because they need external temperatures to regulate their body temperature and, therefore, generally have lower metabolism – are aging less than the endothermes, producing within them heat and obesity.
“People tend to think, for example, that mice age faster because they have a higher metabolism, whereas tortoises grow slower because they have lower metabolism,” Miller said. both well. above and below the known age limitations of endotherms of the same size, suggesting that the animal’s way of regulating its temperature – cold blood compared to warm blood – does not reflect its age or life span. “We did not find metabolic means that ectotherms are getting older, “Miller said. “That relationship was only true for tortoises, which suggests that tortoises are different from ectotherms.”
The protective phenotypes hypothesis suggests that animals with physical or chemical properties that provide protection – such as weapons, spines, shells or poisons – have slow aging and long-term survival. The team wrote that these defective properties enable animals to age slower and, in the case of physical defenses, live longer in size than those without defensive phenotypes, which includes neglected aging – or the lack of aging populations – and extraordinary longevity, “says Anne Bronikowski, accompanying author and professor of integrative biology, Michigan State.
Beth Reinke, first writer and assistant professor of biology at Northeastern Illinois University, also explained, “These different precautions can reduce the mortality rate of animals because they are not eaten by other animals. Thus, they are more likely to live longer. very little. We have found great support for the protective phenotype hypothesis in turtles. Also, this shows that tortoises, as a group, are different. “
Interestingly, the team saw an indiscriminate aging of at least one species of ectotherm group, including frogs and frogs, crocodiles and tortoises. all over the world they are learning about a wide variety of animals.“The ability to integrate all these writers who have spent years and years of work studying each genre is what made it possible for us to get these reliable estimates of aging and longevity based on human data instead of each animal. , “he said.
Source Journal Reference: Beth A. Reinke et al. Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity. Science, 2022 DOI: 10.1126/science.abm0151
