LONDON - Scientists discover that defensive mechanisms, such as shells and venom, may contribute to animals’ ability to stop their own bodies from deteriorating, Andy Gregory reports in the THE INDEPENDENT on Friday.

Turtles have managed to slow down and even completely switch off the ageing process, according to two new studies which subvert the notion of ageing as an inescapable fate.

While no living organism can escape death, scientists have provided the most compelling evidence yet that our cold-blooded compatriots may hold the keys to the long-coveted secret of how to weaken the fatalistic grip of time.

The new studies, both published on Thursday in the journal Science, have found that various species of turtles – and also tortoises, crocodiles and salamanders – have found a way to either slow down or virtually halt senescence, the process of deterioration within the body.

“It sounds dramatic to say that they don’t age at all, but basically their likelihood of dying does not change with age once they’re past reproduction,” said first author Dr Beth Reinke, a biologist at Northeastern Illinois University.

Along with an international team of 114 scientists, Dr Reinke collected data in the wild from 107 populations of 77 species of reptiles and amphibians such as Komodo dragons, garter snakes and tree frogs, in what is billed as the most comprehensive study of ageing and longevity to date.

“Anecdotal evidence exists that some reptiles and amphibians age slowly and have long lifespans, but until now no one has actually studied this on a large scale across numerous species in the wild,” said senior author David Miller, an associate professor of wildlife population ecology at Penn State University.

“If we can understand what allows some animals to age more slowly, we can better understand ageing in humans, and we can also inform conservation strategies for reptiles and amphibians, many of which are threatened or endangered.”

Contrary to many theories, their findings suggest the way an animal regulates its temperature – whether it is cold-blooded (ectothermic) or warm-blooded (endothermic) – is not necessarily indicative of its ageing rate or lifespan, with ectotherms’ ageing rates and lifespans found to range both well above and below the average ageing rates for warm-blooded counterparts of a similar size.

The team also observed negligible ageing in at least one species in each of the cold-blooded groups, including in frogs and toads, crocodilians and turtles.

The other study published on Thursday, led by the University of Southern Denmark, focused on the impact of captivity upon the ageing process of turtles and tortoises.

Looking at turtles and tortoises living in zoos and aquariums, the researchers found that out of 52 species, 75 per cent of them show extremely slow senescence, while 80 per cent of them have slower senescence than modern humans.

The researchers discovered that some of these species were even able to reduce their rate of senescence in response to the improved living conditions in zoos and aquariums, compared to the wild. It was suggested that as their conditions improve, these turtles can allocate more energy to survival rather than protection, thereby extending their lifespans.

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