Why Do Turtles Live So Long? Some Barely Seem to Age

In many turtle species, the risk of dying barely rises with age. Studies from 2022 point to protective shells and a slow pace of life, but there are exceptions.

Curious Mundi Editorial Team · November 4, 2026

Illustration of a large tortoise walking on grass, with growth rings on the plates of its shell.

Turtles live so long because many species age extremely slowly: once they are adults, their risk of dying barely rises as they get older. Two studies published in the journal Science in 2022 link this to their protective shells and a slow pace of life. But not every turtle is long-lived, and none of them are immortal.

What does it mean to say a turtle barely ages?

To biologists, aging is more than adding birthdays. It is the rise in the risk of death and the loss of bodily function as the years go by. In humans that risk climbs steeply: for women in the United States, the yearly chance of dying is about 1 in 2,500 at age 10 and 1 in 24 at age 80.

Scientists call it negligible aging when that curve stays essentially flat. Biologist Beth Reinke of Northeastern Illinois University put it this way: in these animals, the likelihood of dying does not change with age once they are past reproduction. If the risk is 1% a year at age 10, it is still 1% at age 100.

What did the 2022 studies find?

In June 2022, Science published two complementary papers. One, led by Penn State and Northeastern Illinois University, brought together 114 scientists and data from wild populations. The other, from the University of Southern Denmark, looked at turtles, terrapins and tortoises living in zoos and aquariums.

Study	What it analyzed	Main finding
Reinke and colleagues (Penn State and Northeastern Illinois)	107 wild populations of 77 reptile and amphibian species	Little or no sign of aging in several turtle species
Da Silva and colleagues (University of Southern Denmark)	52 turtle and tortoise species in zoos and aquariums	Extremely slow aging in about 75% of them; about 80% age more slowly than modern humans

The wild-population study also showed huge variety among cold-blooded animals: lifespan measured from first reproduction ranged from 1 to 137 years, a wider spread than seen in birds and mammals.

How much do shells and metabolism matter?

A popular idea holds that cold-blooded animals live longer because their metabolism is slow. The wild-population study tested this and, overall, did not support it: aging rates in reptiles and amphibians fall both above and below those of mammals and birds of similar size. The link with metabolism showed up only in turtles, which suggests they are a special case.

The explanation with the strongest support was different: protective traits, such as the hard shell most turtles carry, contribute to slower aging. The reasoning is that when adults rarely get eaten or injured, it pays to invest in body maintenance, because the animal has a real chance of living and breeding for many years. Physical defenses shape the lives of many animals, like zebra stripes, which seem to keep biting flies away.

Which turtles live the longest?

The most famous example is Jonathan, a Seychelles giant tortoise who lives on the grounds of the governor's residence on St Helena, a British island in the South Atlantic. He arrived on the island in 1882 already fully grown, at least 50 years old, so his hatching is estimated at around 1832. Guinness World Records recognizes him as the oldest living land animal and the oldest chelonian ever recorded. In 2026 he would be about 194, and that estimate is considered conservative.

In the Danish study, the Aldabra giant tortoise had an aging rate of zero, and an Asian species, the black marsh turtle (Siebenrockiella crassicollis), even had a negative rate: in the population studied, the risk of dying went down with age.

Do all turtles live a long time?

No. If about 80% of the species studied in captivity age more slowly than we do, the other 20% age at the same pace or faster. The Egyptian tortoise (Testudo kleinmanni), for example, has a positive aging rate, like humans.

Aging slowly is not the same as being immortal, either. The Danish researchers point out that all of these animals eventually die from unavoidable causes such as illness. They also saw some species slow their aging when they lived in better conditions than in the wild, a sign that environment matters too.

For us, who watch time pass in hair that turns gray and plenty of other signs, turtles are proof that aging does not follow one rule across the living world. Some species, armored and in no hurry at all, seem to have struck a much better deal with time than we have.