Crocodiles, salamanders and turtles could potentially hold the secret to humans living until they are 150, experts hope.
For decades, scientists have struggled in their quest to find an anti-ageing potion.
Experiments on cold-blooded animals like turtles, which famously live longer than other animals their size, could change their fortunes.
Michigan State University researchers are hopeful they will uncover ‘traits’ that can also be targeted in humans.
The team have yet to pinpoint any potential longevity targets and any meaningful discovery could still be years off, however.
The armoured hide of a fearsome crocodile could partly explain why they are have developed such long lifespans scientists say, and furthermore, unpicking the biology behind the process could one day help extend human lifespans
Lead researcher and biologist Professor Anne Bronikowski said: ‘Understanding the comparative landscape of aging across animals can reveal flexible traits that may prove worthy targets for biomedical study related to human aging.’
Fellow author Professor David Miller, from Pennsylvania State University, added: ‘If we can understand what allows some animals to age more slowly, we can better understand aging in humans.’
He added that, in theory, it may help inform conservation strategies for threatened or endangered species.
Published in the journal Science, experts looked at 77 different species of reptiles and amphibians in habitats located around the world.
Unable to stand on one leg? You could be at risk of an early death
Those who wobble when trying to stand on one leg are at risk, according to the latest study.
Researchers in Brazil found that those who couldn’t complete the ‘Flamingo’ exercise were nearly twice as likely to die early as those who could.
More than 1,700 participants, aged 50 to 75, underwent various fitness tests, including standing on one leg for 10 seconds without any support.
This involved placing the front of one foot on the back of the opposite lower leg, while keeping arms by the sides and looking straight ahead.
Over the course of the study — conducted by researchers at Exercise Medicine Clinic CLINIMEX in Rio de Janeiro — which saw each participant monitored for an average of seven years, 123 people died.
The results, published in the British Journal of Sports Medicineshow that those unable to stand unsupported on one leg for 10 seconds were 84 per cent more likely to die from any cause.
By no means does it mean balance problems are the actual cause of death.
But lead researcher Dr Claudio Gil Araujo said good levels of balance are needed for daily life and a loss of balance is ‘detrimental for health’.
Therefore, the test ‘provides rapid and objective feedback for the patient and health professionals regarding static balance’, according to the team. They said it ‘adds useful information regarding mortality risk in middle-aged and older men and women’.
Some showed signs of ‘negligible ageing’.
While all living organisms age and die, not all creatures follow the same pattern of weakening and deterioration to old age and death.
Professor Miller added: ‘Negligible aging means if an animal’s chance of dying in a year is 1 per cent at age 10, if it is alive at 100 years, it’s chance of dying is still 1 per cent.’
‘By contrast, in adult females in the US, the risk of dying in a year is about 1 in 2,500 at age 10 and 1 in 24 at age 80.
‘When a species exhibits negligible senescence (deterioration), aging just does not happen.’
Researchers credited this, largely, to turtles having hard shells to protect them from being eaten. Crocodiles are protected by their thick scales, while salamanders can fall back on their poisonous skin.
None of these, obviously, apply to humans.
Yet scientists think other answers as to how they can defy ageing could be lurking deeper within their bodies.
Today’s findings also help upturn previous scientific consensus that linked the long lifespan of some reptiles to their slower metabolism.
Because cold-blooded creatures draw energy from the environment, as opposed to mammals like humans which need to burn calories to keep warm, they don’t need to eat as much giving them slower metabolisms.
This was previously thought to be the key behind some reptiles being able to live up to 190 years.
However, the new analysis found there was no link between slower metabolism and longer lifespans when comparing their 77 species with similar sized warm-blooded creatures.
The oldest land-dwelling animal in the world is currently a giant tortoise in the Seychelles named Jonathan, who is 190.
Data from the Office of National Statistics shows life expectancy at birth in the UK is 79 years for men and just under 83 years for women.
But lifespans of 150 years, once thought of as a distant pipe dream are now edging closer to reality according to some scientists.
In March, this year leading experts on ageing said children born in 2070 could live until the age of 150 thanks to advances in reverse-ageing technology.
This declaration followed a pioneering study earlier that month which managed to safely reverse the ageing process in elderly mice.