Researchers have discovered creatures that do not appear to age. What exactly does this imply for human beings?

How have turtles been able to defy the effects of aging?

 

Everyone will eventually die, but certain animals don't appear to age like humans do—at least not all of them.

 

According to the findings of two recent studies that were published in the journal Science on Thursday (June 23), turtles and tortoises exhibit astonishingly slow rates of aging. Some animals might not mature at all if they are kept in captivity since they do not have the stress of having to obtain food and avoid being eaten by other animals.

 

Rita de Silva, who was a biologist at the University of Southern Denmark when she did the research and is now a biologist at the Universidade do Porto in Portugal, and who was the primary author of one of the studies, described the findings as "very exciting." Even though modern humans live in a world that poses fewer threats to their day-to-day survival than the environments in which our early predecessors lived, this advantage has not yet been discovered by modern humans. This fact adds another layer of intrigue to an already intriguing topic.

 

According to da Silva, who spoke to Live Science about the topic, "as modern people, we tend to live in extremely good conditions; therefore, the environment for us would be close to ideal [as well]." "And yet, we are unable to slow down the rate at which we are aging."

 

It is a little bit of a mystery how the turtles can prevent aging, but the answer may lie in their shells.

 

The aging process and passing away

 

To begin comprehending the anti-aging superpower possessed by these turtles, it is necessary first to become familiar with the mind-boggling concept that while death is unavoidable, aging might not be. The idea of age can be construed in a few different ways. One is longevity, which refers to a species's potential for living the longest. Scientists typically define longevity as the age at which a significant proportion, say 95 percent, of adults in a population have died. According to this, the average lifespan of a human being is approximately 100 years.

 

Senescence is an alternative way to think about the aging process. Senescence is the process by which an organism gradually loses function as it ages. It is simple to observe this phenomenon in human beings: as people get older, their immune systems weaken, their bones become brittle, and their energy levels decrease. In addition, the probability of passing away increases statistically with each passing year of age. According to the Social Security Administration's actuarial calculations, a 50-year-old male in the United States has a 0.48 percent chance of dying within the next calendar year. A man who is 80 years old has a 5.6% risk of passing away within the next 12 months. A man over the age of 100 has a nearly 35% chance of not seeing the New Year's Eve countdown.

 

According to the findings of recent research, the accumulation of risk in turtles occurs much, much more slowly than it does in other animals. In some situations, it may not even exist at all. To put it another way, there are some animals in which becoming older does not make one more susceptible to dying. Suppose there is even a one percent probability of mortality each year. In that case, it is unavoidable that the age-defying reptile's number will ultimately come up, and hence it is inevitable that all turtles will pass away at some point in the future. On the other hand, this risk of passing away could be the same regardless of the turtle's age: 5, 25, or even 125 years old in the case of some species that live exceptionally long lives.

 

Researchers have known for a very long time that turtles and tortoises can have exceptionally lengthy lifespans. This year, for example, a Seychelles giant tortoise (Aldabrachelys gigantic hololissa) named Jonathan celebrated his 190th birthday, making him the oldest tortoise in history, as well as the oldest land mammal ever recorded. According to a previous report by Live Science, research on the biology of turtles and tortoises suggests that these reptiles can quickly eliminate damaged cells and that they are resistant to DNA damage that accumulates over time as a result of cells dividing; this protects individuals even as they enter extreme old age.

 

The development of the aging process

 

When it comes to evolution, the most pressing question is how turtles managed to amass their extraordinary anti-aging abilities and why the rest of us are doomed to age inevitably. Researchers looked into this subject in two recent studies, one of which focused on wild turtle and tortoise populations and the other on captive turtle and tortoise populations.

 

Species360 Zoological Information Management System is software that is used by zoos to track data regarding animal husbandry. The research that de Silva directed looked at 52 species that were being kept in captivity and whose records were available in the system. They discovered that around seventy-five percent of species displayed either nil or a negligible aging rate. There was a large range of uncertainty about the rate at which a species ages in certain circumstances, but in other cases, the numbers were consistent around zero, indicating that these species probably do not period at all or age very slowly. The Greek tortoise (Testudo graeca) and the black marsh turtle are two examples of animals that have consistently shown minor signs of aging (Siebenrockiella crassicollis). The Aldabra giant tortoise, scientifically known as Aldabrachelys gigantea, has been seen to have an almost nonexistent rate of aging and an exceptionally long average lifespan of at least 60 years when kept in captivity. The Chelonoidis niger tortoise, often known as the Galápagos tortoise, was one of the species that the scientist Charles Darwin investigated during his trip to the islands of the same name in 1835. Darwin was there to study various animals that were native to the Galápagos Islands.

 

The second study, which a separate research group carried out, investigated the phenomenon of aging in wild populations. One theory that has been around for a long time to explain why turtles age so slowly is that because they are cold-blooded, they do not need to expend energy on regulating their body temperature, which may enable them to direct that energy into cellular repair rather than temperature maintenance. Beth Reinke, a biologist at Northeastern Illinois University and the lead author of this study, along with co-author David Miller, a wildlife population ecologist at Pennsylvania State University, and their colleagues wanted to put this theory to the test by comparing the aging rates of cold-blooded animals to the aging rates of warm-blooded animals while controlling for factors such as body size.

 

To accomplish this, they needed to collect data from a variety of scientists located in different parts of the world. These scientists mark or tag animals that are a part of a wild population, and then they return year after year to check on whether or not they were successful in recapturing those animals. These extensive field investigations are one of the few ways to gain knowledge about the lifespans of wild animals as well as the demography of their populations.

 

In an interview that Reinke gave to Live Science, he said, "I'm just so in awe that we were able to get so many academics eager to submit their data that they've sweated hours for."

 

The researchers were surprised to discover that cold-blooded animals did not age more slowly than warm-blooded animals did. Instead, the cold-blooded creatures displayed a much wider range of the effects of aging, with some cold-blooded creatures aging more quickly than similarly sized warm-blooded animals and some cold-blooded creatures aging more slowly. At least one species in each of the four groups (crocodilians, frogs and toads, squamate lizards, and turtles) showed no signs of aging at all. However, the turtles stood out, just as they did in the study that de Silva and colleagues conducted.

 

According to what Miller shared with Live Science, "What we found is that there are some pretty constant characteristics in turtles, which is that they live for a very long period of time and they mature really slowly."

 

The researchers explored a few additional potential factors that would explain why some animals age quickly while others age slowly because the cold-bloodedness hypothesis was unable to explain the delayed aging observed in this species. They examined the average local temperatures throughout the range of each species and found a variety of different patterns: The pace of aging sped up among reptiles living in hotter environments, but amphibians aged more slowly in warmer climates. They also discovered that longevity was associated with later sexual maturity, which indicates a slower life pace for long-lived organisms that have a cold-blooded metabolic system.

 

How to pass away without getting old

 

However, one of the fascinating discoveries was that the cold-blooded animals with the slowest rates of aging were also the ones that had the strongest defenses to protect them from being eaten by other animals. In particular, having some form of physical protection, such as a shell, was linked to slower aging rates.

 

Because their shells prevent them from being consumed, turtles have a lower risk of dying from causes that are external to them compared to other species that do not have this protection. (Consider the disparity between the chances of a young rabbit surviving an attack by a fox and those of a young box turtle.) According to Miller, the fact that the death rate is so low across the board suggests that turtles have a good chance of living long enough to reap the benefits of the cellular defenses they have against aging.

 

"If a significant number of animals are eaten or perish from sickness, "There aren't enough of them that survive long enough to reap any benefits from the kinds of biological activities that slow down the aging process," Miller said. Animals' protective traits may allow them to survive long enough for evolution to work on anti-aging defenses by enabling them to live longer.

 

Miller believes that there are possible evolutionary parallels between humans and captive turtles. Many people live in comfortable surroundings now, with easy access to food and shelter, similar to how captive turtles live their lives. According to Miller, although the slow aging process of turtles and tortoises may appear to be something to aspire to, humans are also not slouched when it comes to lifespan. People age more quickly than the typical turtle but significantly more slowly than a great many other species.

 

According to Reinke, a significant amount of additional research is necessary before reaching that point. The biology of turtles and tortoises could help reveal the secrets to anti-aging treatments for people. More research is required to get a better understanding of the evolution of aging in other animals. For instance, there isn't a lot of information available on species that live exceptionally long lives, particularly when looking at the question of whether or not the pace of aging speeds up at some point in creatures that live very long lives. For instance, Jonathan the tortoise is unable to see, hear, or smell, and he needs to be fed by hand. An editorial that was published in conjunction with the two findings was written by biologist Steven Austad of the University of Alabama in Birmingham and aging researcher Caleb Finch of the University of Southern California.

 

Even if many of these fascinating species do not experience a mortality rate that considerably increases with age, as Austad and Finch stated, "some certainly incur infirmities of aging."

Article source : https://www.livescience.com/turtles-dont-age

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