There are three Mode of death: injury, illness or old age. Humans have gotten better at avoiding the first two over time, but aging—the gradual deterioration of bodily functions with age—is inevitable. Still, some species seem to be doing better than others: Take the Hydra, for example, a small freshwater creature that some scientists think may be immortal. Last year, a naked mole rat made headlines for turning 39, five times the normal lifespan for a rodent of a similar size. Just a few months ago, a giant Aldabra tortoise named Jonathan celebrated his 190th birthday, making him the world’s longest-lived land animal.
Cases like this begs the question: Is it possible to get rid of aging?
The authors of a study published in science Said yes last month. Well, if you are a turtle. Through extensive analysis of 52 species of sea turtles, including aquatic and land turtles, a team of four scientists found that most of them exhibited unusually slow (and in some cases negligible) Aging. This does not make them immortal; turtles can still die from disease or injury. But unlike birds and mammals, their overall mortality risk does not increase with age. “We confirmed what was suspected a long time ago but never proved,” said biodemographer Fernando Corcello of the University of Southern Denmark.
Aging rate is a measure of how the risk of death increases with age in a biological population. For birds and mammals, this risk is thought to increase exponentially with age. But for most turtle species in the study, the rate was almost flat, regardless of how old they were.
Colchero and his colleagues also found that the environment in which the animals lived also played a role. “Sea turtles and tortoises, based on our results compared to wild animals, can actually change their rate of aging significantly when conditions improve,” he said, referring to protection from predators, controlled climates and unlimited access to food and other factors and shelters. This differs from previous work using primate data, which reported increased lifespan due to better living conditions, but no significant reduction in mortality due to slower aging.
What is given? Some evolutionary theories suggest that aging is the result of an energy tradeoff. Most mammals and birds stop growing once they reach sexual maturity, when their energy is prioritized for reproduction over cellular repair, Colchero said. Without adequate maintenance to deal with wear and tear, the body becomes more vulnerable to age-related chronic diseases and injuries or infections. “But many reptiles don’t. They keep growing, which means they seem to be very effective at repairing damage and keeping the body functioning properly,” he said.
Animals with this quality are prime candidates to escape aging, according to biologist Rita da Silva, who led the study with Colchero. To prove it, an idea that’s been around since the 1990s, the researchers gathered demographic information from the Zoological Information Management System, a database of zoo and aquarium records maintained by the nonprofit Species360. They selected species with data on at least 110 animals and focused only on sea turtles that live in freshwater or land.
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