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From Giant Tortoises to Immortal Jellyfish, These Impressive Animals Are Eight of the Longest-Living Species on Earth

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Wednesday, December 11, 2024

Life is short, the old saying goes, but in the world of animals, we humans are pretty fortunate: Our species is quite long-lived. With 122 being the oldest documented age, humans can enjoy decades more life than most fish, birds and mammals—including our primate relatives. But we’re not alone in experiencing longevity. Other rare species reach ages marked in centuries, and each class of animals boasts individuals that are unusually long-lived compared to their peers. Aging wild animals isn’t always easy—they don’t have birth certificates. But we’ve searched the scientific record to identify some of the world’s oldest species and revealed their secrets to staying alive. Giant tortoises are the longest-living reptiles Jonathan the Seychelles giant tortoise at 185 years old Gianluigi Guercia / AFP via Getty Images The world’s oldest living land animal, Jonathan the Seychelles giant tortoise, celebrates his unofficial 192nd birthday this December 4. His estimated birth year is 1832, the year Andrew Jackson won re-election. He was fully mature, thus at least 50, when he was gifted to the governor of Saint Helena island in 1882. But nobody knows his real age, and some experts suspect Jonathan was probably born even earlier. And this ancient individual isn’t an outlier among his kind. Seychelles giant tortoises average a 150-year life span, and related species can be similarly long-lived. How? Genetic studies of Galápagos giant tortoises revealed variants that aid cancer suppression, anti-inflammatory immune responses and DNA repair. When some tortoise cells are subjected to age-related stresses, they tend to self-destruct before they are damaged in ways that could produce cancer or other fatal illnesses. Other research suggests that part of the tortoise’s secret lies in its shell. A study of 77 species of reptiles and amphibians showed that species with protective shells aged five times more slowly than those without the coverings. One theory holds that since shells frequently prevent tortoises from being eaten by predators, shelled species tend to live longer, and over time that may have helped to produce evolutionary pressures to age more slowly. Olms, the cave-dwelling salamanders, are the longest-living amphibians A young olm is released into an aquarium in a cave in Slovenia. Ure Makovec / AFP via Getty Images In the lightless caves of Croatia and Slovenia, the olm cave salamander has adapted superpowers to thrive in an isolated environment across generations over some 20 million years. Olms enjoy extreme senses of smell and hearing, and the ability to hunt by detecting faint electrical fields of other animals in the water nearby. They have also become very long-lived among amphibians, averaging 69 years and reaching ages of 100 or perhaps more. Those estimates come from research out of a cave laboratory in Moulis, France, where scientist have tracked olm births and deaths for some 70 years. Adult olms retain characteristics of their larval youth, like external gills, and show few signs of aging even as the decades pile up. But the reasons why they live so long aren’t clear. These salamanders go through life slowly with a low metabolism. They can go for years without eating and even spend years without moving much from a single location. But their metabolisms aren’t significantly lower than those of relatives that don’t live nearly as long. The olm’s caves are largely free from predators and external threats, so it’s possible that the environment encourages very high survival rates that in turn have somehow enabled olms to evolve extreme life spans. Greenland sharks are the longest-living fish A Greenland shark off the coast of Nunavut Hemming1952 via Wikipedia under CC By-SA 4.0 Could a contemporary of William Shakespeare still be swimming in the sea? Greenland sharks inhabit the deep, dark, frigid waters of the Arctic and North Atlantic oceans—and they do so for an astoundingly long time. Radiocarbon dating techniques on the fish’s eye lenses have found living sharks that are around 400 years old, according to a 2016 study, which means they could have been alive during the Bard’s days. In the frigid depths, the cold-blooded animals’ movements and metabolism slow dramatically. Greenland sharks’ metabolic rate is “just above a rock,” Chris Lowe, a shark biologist at the California State University at Long Beach, told Smithsonian magazine in 2016. Greenland sharks are slow-growing, less than half an inch per year, but live so long that mature specimens reach more than 19 feet in length. These sharks may not reach reproductive age until they are 150 years old—longer than any human has ever survived. Based on their growth rates and the size of some sharks, their maximum age could be as much as 500 years. In September 2024, an international team sequenced the shark’s very large genome—a genetic code of 6.5 billion base pairs, twice as long as the human genome. Greenland sharks boast high numbers of repetitive or duplicate genes. That’s often considered detrimental to a genome, but in this case it may be beneficial for longevity because many of the duplicated genes help to repair DNA damage in cells. Termite queens are the longest-living insects A termite queen in captivity China Photos / Getty Images Life is fleeting for most insects. “Generally insect life spans are measured in weeks to months,” says Floyd Shockley, an entomologist at the Smithsonian’s National Museum of Natural History. These species tend to reproduce at a tender age, having many young as quickly as possible, because their days are numbered. But some social insects, like termites, employ a different strategy, and it enables their queens to defy death for 50 years or more. Among these insects, most individuals—the workers—are largely sterile and live just a few months. They spend that time supporting the queen’s efforts as an egg-laying machine—in some cases she’ll produce thousands a day for many years on end. “The queens reproduce nonstop upon reaching adulthood, and the reproductive cycle has many aspects to it that result in enhanced cellular regeneration,” Shockley explains. This genetic ability to regenerate cells keeps some queens going for decades, arresting their aging until they literally give out and run out of eggs. “At that point,” Shockley says, “they rapidly decline and die.” Laysan albatrosses are the longest-living wild birds An older albatross named Wisdom covers a recently hatched chick in 2011 at Midway Atoll. John Klavitter / U.S. Fish and Wildlife Service via Wikipedia / Public Domain Birds are relatively long-lived in the animal kingdom, averaging two to three times the life span of mammals of the same size, studies show. This longevity might be related to birds’ ability to fly. As evolution fine-tuned bird biology to engineer flight, building systems like strong muscles and efficient ways to process oxygen, it may have helped them to stay healthier longer—as well as enable them to fly away from potentially lethal situations. Most adult birds don’t show many obvious physical signs of aging, which makes it difficult to know just how long they have been alive in the wild. But one unusual example, a Laysan albatross named Wisdom, is at least 74 years old and has just laid another egg. The oldest-known wild bird in the world, Wisdom was banded in 1956. During her annual wanderings she returns to Midway Atoll each year, usually in December. Scientists estimate that Wisdom has flown over three million miles in her long life, and fledged as many as 30 chicks. Sponges are the longest-living invertebrates The glass sponge Euplectella aspergillum NOAA via Wikipedia / Public Domain Sponges aren’t the most dynamic animals; rooted to a spot on the seafloor, these filter feeders may appear more similar to plants than animals. But they have at least one jaw-dropping ability—survival. Glass sponge reefs found off British Columbia’s north coast are among the oldest in the entire ocean and have survived for more than 9,000 years. In the East China Sea, scientists discovered the skeleton of a glass sponge that had lived for some 11,000 years. The sponge is so ancient that its remains constitute an archive of ancient climate in the sea. Under chemical analysis, scientists were able to reconstruct past environmental changes like ocean temperature shifts and the eruptions of underwater seamounts, which left their marks on the ancient sponge. Fossils show that these sponges aren’t just long-lived individuals. As a group they are some of the earliest animals to appear on Earth. They may have been around as long as 890 million years ago—more than 600 million years before the dinosaurs emerged. Elephants are some of the longest-living land mammals An elephant mother walks with her baby in Kenya. Eric Lafforgue / Art in All of Us / Corbis via Getty Images Elephant memories are long, and so are their lives. African elephants can live up to 70 years, while their slightly smaller Asian elephant relatives may reach 60 years of age. Big mammals like whales and elephants, which are less likely to die from predators or other accidents, tend to live longer lives. This in turn can spur evolutionary genetic and metabolic investments that protect against, or repair, the damage life exerts on cells. Elephants copy tumor-suppressing genes, for example, so that one can function if the other is damaged. That kind of anti-cancer adaptation is unlikely to arise in a short-lived small mammal, like a field mouse, that’s soon to become something’s dinner. And while many species strive to reproduce before they die but don’t have a huge role once their reproductive days have passed, elephants are different. These giants have a social structure that values elders for many years after their peak reproductive period is over. Studies show that elderly female elephants are leaders, valued for their roles as caregivers for the young and for their experience and knowledge to evaluate predatory threats and make good decisions for the group. Immortal jellyfish are the longest-living invertebrates The immortal jellyfish: is it possible to live forever? These tiny jellyfish have been drifting around the oceans since before the days of the dinosaurs—but how long has a single jellyfish lived? It appears to be biologically possible that, if not swallowed up by predators or killed by other factors, an immortal jellyfish could live indefinitely. Like other jellyfish, the species’ fertilized eggs develop into a larva form, which then drops to the seafloor and grows into a colony of polyps. The polyps later morph into the recognizable, free-floating jellyfish forms known as medusas. But incredibly, when faced with threats from injury to starvation, the immortal jellyfish can reverse the process, turning the clock backward. First the gelatinous layer thins out and the jellyfish settles on the bottom, where it becomes a cyst-like mass of cells. All features of the familiar “medusa” shape disappear. But within a few days it starts to show polyp features, and it begins the life cycle anew. “The process is a true metamorphosis, albeit in opposite direction to the normal developmental cycle,” says Maria Pia Miglietta, who studies the evolution and ecology of the immortal jellyfish at Texas A&M University. Miglietta adds that the transformation from jellyfish to polyp may involve transdifferentiation—a process in which mature cells transform from one type to another entirely different type of cell. Miglietta says that while the jellyfish life cycle has been reversed many times in the lab, nobody knows how often it happens or how long the jellyfish might survive in the wild. “Studying these animals in the ocean is hard,” she says, “and we haven’t figured out how to follow a two-millimeter jellyfish and see what happens to it.”Full Credit for Main Image: Hemming1952 via Wikipedia under CC By-SA 4.0; John Klavitter / U.S. Fish and Wildlife Service via Wikipedia / Public Domain; Eric Lafforgue / Art in All of Us / Corbis via Getty Images; China Photos / Getty Images; Gianluigi Guercia / AFP via Getty Images; NOAA via Wikipedia / Public Domain Get the latest Science stories in your inbox.

Aging gracefully comes naturally to these creatures, which can live for hundreds, and sometimes even thousands, of years

Life is short, the old saying goes, but in the world of animals, we humans are pretty fortunate: Our species is quite long-lived. With 122 being the oldest documented age, humans can enjoy decades more life than most fish, birds and mammals—including our primate relatives.

But we’re not alone in experiencing longevity. Other rare species reach ages marked in centuries, and each class of animals boasts individuals that are unusually long-lived compared to their peers. Aging wild animals isn’t always easy—they don’t have birth certificates. But we’ve searched the scientific record to identify some of the world’s oldest species and revealed their secrets to staying alive.

Giant tortoises are the longest-living reptiles

Jonathan the Seychelles Giant Tortoise
Jonathan the Seychelles giant tortoise at 185 years old Gianluigi Guercia / AFP via Getty Images

The world’s oldest living land animal, Jonathan the Seychelles giant tortoise, celebrates his unofficial 192nd birthday this December 4. His estimated birth year is 1832, the year Andrew Jackson won re-election. He was fully mature, thus at least 50, when he was gifted to the governor of Saint Helena island in 1882. But nobody knows his real age, and some experts suspect Jonathan was probably born even earlier. And this ancient individual isn’t an outlier among his kind. Seychelles giant tortoises average a 150-year life span, and related species can be similarly long-lived. How?

Genetic studies of Galápagos giant tortoises revealed variants that aid cancer suppression, anti-inflammatory immune responses and DNA repair. When some tortoise cells are subjected to age-related stresses, they tend to self-destruct before they are damaged in ways that could produce cancer or other fatal illnesses. Other research suggests that part of the tortoise’s secret lies in its shell. A study of 77 species of reptiles and amphibians showed that species with protective shells aged five times more slowly than those without the coverings. One theory holds that since shells frequently prevent tortoises from being eaten by predators, shelled species tend to live longer, and over time that may have helped to produce evolutionary pressures to age more slowly.

Olms, the cave-dwelling salamanders, are the longest-living amphibians

Olm
A young olm is released into an aquarium in a cave in Slovenia. Ure Makovec / AFP via Getty Images

In the lightless caves of Croatia and Slovenia, the olm cave salamander has adapted superpowers to thrive in an isolated environment across generations over some 20 million years. Olms enjoy extreme senses of smell and hearing, and the ability to hunt by detecting faint electrical fields of other animals in the water nearby. They have also become very long-lived among amphibians, averaging 69 years and reaching ages of 100 or perhaps more. Those estimates come from research out of a cave laboratory in Moulis, France, where scientist have tracked olm births and deaths for some 70 years.

Adult olms retain characteristics of their larval youth, like external gills, and show few signs of aging even as the decades pile up. But the reasons why they live so long aren’t clear. These salamanders go through life slowly with a low metabolism. They can go for years without eating and even spend years without moving much from a single location. But their metabolisms aren’t significantly lower than those of relatives that don’t live nearly as long. The olm’s caves are largely free from predators and external threats, so it’s possible that the environment encourages very high survival rates that in turn have somehow enabled olms to evolve extreme life spans.

Greenland sharks are the longest-living fish

Greenland Shark
A Greenland shark off the coast of Nunavut Hemming1952 via Wikipedia under CC By-SA 4.0

Could a contemporary of William Shakespeare still be swimming in the sea? Greenland sharks inhabit the deep, dark, frigid waters of the Arctic and North Atlantic oceans—and they do so for an astoundingly long time. Radiocarbon dating techniques on the fish’s eye lenses have found living sharks that are around 400 years old, according to a 2016 study, which means they could have been alive during the Bard’s days.

In the frigid depths, the cold-blooded animals’ movements and metabolism slow dramatically. Greenland sharks’ metabolic rate is “just above a rock,” Chris Lowe, a shark biologist at the California State University at Long Beach, told Smithsonian magazine in 2016. Greenland sharks are slow-growing, less than half an inch per year, but live so long that mature specimens reach more than 19 feet in length. These sharks may not reach reproductive age until they are 150 years old—longer than any human has ever survived. Based on their growth rates and the size of some sharks, their maximum age could be as much as 500 years.

In September 2024, an international team sequenced the shark’s very large genome—a genetic code of 6.5 billion base pairs, twice as long as the human genome. Greenland sharks boast high numbers of repetitive or duplicate genes. That’s often considered detrimental to a genome, but in this case it may be beneficial for longevity because many of the duplicated genes help to repair DNA damage in cells.

Termite queens are the longest-living insects

Termite Queen
A termite queen in captivity China Photos / Getty Images

Life is fleeting for most insects. “Generally insect life spans are measured in weeks to months,” says Floyd Shockley, an entomologist at the Smithsonian’s National Museum of Natural History. These species tend to reproduce at a tender age, having many young as quickly as possible, because their days are numbered.

But some social insects, like termites, employ a different strategy, and it enables their queens to defy death for 50 years or more. Among these insects, most individuals—the workers—are largely sterile and live just a few months. They spend that time supporting the queen’s efforts as an egg-laying machine—in some cases she’ll produce thousands a day for many years on end. “The queens reproduce nonstop upon reaching adulthood, and the reproductive cycle has many aspects to it that result in enhanced cellular regeneration,” Shockley explains. This genetic ability to regenerate cells keeps some queens going for decades, arresting their aging until they literally give out and run out of eggs. “At that point,” Shockley says, “they rapidly decline and die.”

Laysan albatrosses are the longest-living wild birds

Wisdom the Laysan Albatross
An older albatross named Wisdom covers a recently hatched chick in 2011 at Midway Atoll. John Klavitter / U.S. Fish and Wildlife Service via Wikipedia / Public Domain

Birds are relatively long-lived in the animal kingdom, averaging two to three times the life span of mammals of the same size, studies show. This longevity might be related to birds’ ability to fly. As evolution fine-tuned bird biology to engineer flight, building systems like strong muscles and efficient ways to process oxygen, it may have helped them to stay healthier longer—as well as enable them to fly away from potentially lethal situations.

Most adult birds don’t show many obvious physical signs of aging, which makes it difficult to know just how long they have been alive in the wild. But one unusual example, a Laysan albatross named Wisdom, is at least 74 years old and has just laid another egg. The oldest-known wild bird in the world, Wisdom was banded in 1956. During her annual wanderings she returns to Midway Atoll each year, usually in December. Scientists estimate that Wisdom has flown over three million miles in her long life, and fledged as many as 30 chicks.

Sponges are the longest-living invertebrates

Glass Sponge
The glass sponge Euplectella aspergillum NOAA via Wikipedia / Public Domain

Sponges aren’t the most dynamic animals; rooted to a spot on the seafloor, these filter feeders may appear more similar to plants than animals. But they have at least one jaw-dropping ability—survival. Glass sponge reefs found off British Columbia’s north coast are among the oldest in the entire ocean and have survived for more than 9,000 years.

In the East China Sea, scientists discovered the skeleton of a glass sponge that had lived for some 11,000 years. The sponge is so ancient that its remains constitute an archive of ancient climate in the sea. Under chemical analysis, scientists were able to reconstruct past environmental changes like ocean temperature shifts and the eruptions of underwater seamounts, which left their marks on the ancient sponge.

Fossils show that these sponges aren’t just long-lived individuals. As a group they are some of the earliest animals to appear on Earth. They may have been around as long as 890 million years ago—more than 600 million years before the dinosaurs emerged.

Elephants are some of the longest-living land mammals

Elephants
An elephant mother walks with her baby in Kenya. Eric Lafforgue / Art in All of Us / Corbis via Getty Images

Elephant memories are long, and so are their lives. African elephants can live up to 70 years, while their slightly smaller Asian elephant relatives may reach 60 years of age.

Big mammals like whales and elephants, which are less likely to die from predators or other accidents, tend to live longer lives. This in turn can spur evolutionary genetic and metabolic investments that protect against, or repair, the damage life exerts on cells. Elephants copy tumor-suppressing genes, for example, so that one can function if the other is damaged. That kind of anti-cancer adaptation is unlikely to arise in a short-lived small mammal, like a field mouse, that’s soon to become something’s dinner.

And while many species strive to reproduce before they die but don’t have a huge role once their reproductive days have passed, elephants are different. These giants have a social structure that values elders for many years after their peak reproductive period is over. Studies show that elderly female elephants are leaders, valued for their roles as caregivers for the young and for their experience and knowledge to evaluate predatory threats and make good decisions for the group.

Immortal jellyfish are the longest-living invertebrates

The immortal jellyfish: is it possible to live forever?

These tiny jellyfish have been drifting around the oceans since before the days of the dinosaurs—but how long has a single jellyfish lived? It appears to be biologically possible that, if not swallowed up by predators or killed by other factors, an immortal jellyfish could live indefinitely.

Like other jellyfish, the species’ fertilized eggs develop into a larva form, which then drops to the seafloor and grows into a colony of polyps. The polyps later morph into the recognizable, free-floating jellyfish forms known as medusas.

But incredibly, when faced with threats from injury to starvation, the immortal jellyfish can reverse the process, turning the clock backward. First the gelatinous layer thins out and the jellyfish settles on the bottom, where it becomes a cyst-like mass of cells. All features of the familiar “medusa” shape disappear. But within a few days it starts to show polyp features, and it begins the life cycle anew.

“The process is a true metamorphosis, albeit in opposite direction to the normal developmental cycle,” says Maria Pia Miglietta, who studies the evolution and ecology of the immortal jellyfish at Texas A&M University. Miglietta adds that the transformation from jellyfish to polyp may involve transdifferentiation—a process in which mature cells transform from one type to another entirely different type of cell.

Miglietta says that while the jellyfish life cycle has been reversed many times in the lab, nobody knows how often it happens or how long the jellyfish might survive in the wild. “Studying these animals in the ocean is hard,” she says, “and we haven’t figured out how to follow a two-millimeter jellyfish and see what happens to it.”

Full Credit for Main Image: Hemming1952 via Wikipedia under CC By-SA 4.0; John Klavitter / U.S. Fish and Wildlife Service via Wikipedia / Public Domain; Eric Lafforgue / Art in All of Us / Corbis via Getty Images; China Photos / Getty Images; Gianluigi Guercia / AFP via Getty Images; NOAA via Wikipedia / Public Domain

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In Alaska’s Warming Arctic, Photos Show an Indigenous Elder Passing Down Hunting Traditions

An Inupiaq elder teaches his great-grandson to hunt in rapidly warming Northwest Alaska where thinning ice, shifting caribou migrations and severe storms are reshaping life

KOTZEBUE, Alaska (AP) — The low autumn light turned the tundra gold as James Schaeffer, 7, and his cousin Charles Gallahorn, 10, raced down a dirt path by the cemetery on the edge of town. Permafrost thaw had buckled the ground, tilting wooden cross grave markers sideways. The boys took turns smashing slabs of ice that had formed in puddles across the warped road.Their great-grandfather, Roswell Schaeffer, 78, trailed behind. What was a playground to the kids was, for Schaeffer – an Inupiaq elder and prolific hunter – a reminder of what warming temperatures had undone: the stable ice he once hunted seals on, the permafrost cellars that kept food frozen all summer, the salmon runs and caribou migrations that once defined the seasons.Now another pressure loomed. A 211-mile mining road that would cut through caribou and salmon habitat was approved by the Trump administration this fall, though the project still faces lawsuits and opposition from environmental and native groups. Schaeffer and other critics worry it could open the region to outside hunters and further devastate already declining herds. “If we lose our caribou – both from climate change and overhunting – we’ll never be the same,” he said. “We’re going to lose our culture totally.”Still, Schaeffer insists on taking the next generation out on the land, even when the animals don’t come. It was late September and he and James would normally have been at their camp hunting caribou. But the herd has been migrating later each year and still hadn’t arrived – a pattern scientists link to climate change, mostly caused by the burning of oil, gas and coal. So instead of caribou, they scanned the tundra for swans, ptarmigan and ducks.Caribou antlers are stacked outside Schaeffer's home. Traditional seal hooks and whale harpoons hang in his hunting shed. Inside, a photograph of him with a hunted beluga is mounted on the wall beside the head of a dall sheep and a traditional mask his daughter Aakatchaq made from caribou hide and lynx fur.He got his first caribou at 14 and began taking his own children out at 7. James made his first caribou kill this past spring with a .22 rifle. He teaches James what his father taught him: that power comes from giving food and a hunter’s responsibility is to feed the elders.“When you’re raised an Inupiaq, your whole being is to make sure the elders have food,” he said.But even as he passes down those lessons, Schaeffer worries there won’t be enough to sustain the next generation – or to sustain him. “The reason I’ve been a successful hunter is the firm belief that, when I become old, people will feed me,” he said. “My great-grandson and my grandson are my future for food.” That future feels tenuous These days, they’re eating less hunted food and relying more on farmed chicken and processed goods from the store. The caribou are fewer, the salmon scarcer, the storms more severe. Record rainfall battered Northwest Alaska this year, flooding Schaeffer’s backyard twice this fall alone. He worries about the toll on wildlife and whether his grandchildren will be able to live in Kotzebue as the changes accelerate.“It’s kind of scary to think about what’s going to happen,” he said.That afternoon, James ducked into the bed of Schaeffer’s truck and aimed into the water. He shot two ducks. Schaeffer helped him into waders – waterproof overalls – so they could collect them and bring them home for dinner, but the tide was too high. They had to turn back without collecting the ducks. The changes weigh on others, too. Schaeffer’s friend, writer and commercial fisherman Seth Kantner grew up along the Kobuk River, where caribou once reliably crossed by the hundreds of thousands. “I can hardly stand how lonely it feels without all the caribou that used to be here,” he said. “This road is the largest threat. But right beside it is climate change.”The Associated Press receives support from the Walton Family Foundation for coverage of water and environmental policy. The AP is solely responsible for all content. For all of AP’s environmental coverage, visit https://apnews.com/hub/climate-and-environmentCopyright 2025 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.Photos You Should See – December 2025

Changes to polar bear DNA could help them adapt to global heating, study finds

Scientists say bears in southern Greenland differ genetically to those in the north, suggesting they could adjustChanges in polar bear DNA that could help the animals adapt to warmer climates have been detected by researchers, in a study thought to be the first time a statistically significant link has been found between rising temperatures and changing DNA in a wild mammal species.Climate breakdown is threatening the survival of polar bears. Two-thirds of them are expected to have disappeared by 2050 as their icy habitat melts and the weather becomes hotter. Continue reading...

Changes in polar bear DNA that could help the animals adapt to warmer climates have been detected by researchers, in a study thought to be the first time a statistically significant link has been found between rising temperatures and changing DNA in a wild mammal species.Climate breakdown is threatening the survival of polar bears. Two-thirds of them are expected to have disappeared by 2050 as their icy habitat melts and the weather becomes hotter.Now scientists at the University of East Anglia have found that some genes related to heat stress, ageing and metabolism are behaving differently in polar bears living in south-east Greenland, suggesting they may be adjusting to warmer conditions.The researchers analysed blood samples taken from polar bears in two regions of Greenland and compared “jumping genes”: small, mobile pieces of the genome that can influence how other genes work. Scientists looked at the genes in relation to temperatures in the two regions and at the associated changes in gene expression.“DNA is the instruction book inside every cell, guiding how an organism grows and develops,” said the lead researcher, Dr Alice Godden. “By comparing these bears’ active genes to local climate data, we found that rising temperatures appear to be driving a dramatic increase in the activity of jumping genes within the south-east Greenland bears’ DNA.”As local climates and diets evolve as a result of changes in habitat and prey forced by global heating, the genetics of the bears appear to be adapting, with the group of bears in the warmest part of the country showing more changes than the communities farther north. The authors of the study have said these changes could help us understand how polar bears might survive in a warming world, inform understanding of which populations are most at risk and guide future conservation efforts.This is because the findings, published on Friday in the journal Mobile DNA, suggest the genes that are changing play a crucial role in how different polar bear populations are evolving.Godden said: “This finding is important because it shows, for the first time, that a unique group of polar bears in the warmest part of Greenland are using ‘jumping genes’ to rapidly rewrite their own DNA, which might be a desperate survival mechanism against melting sea ice.”Temperatures in north-east Greenland are colder and less variable, while in the south-east there is a much warmer and less icy environment, with steep temperature fluctuations.DNA sequences in animals change over time, but this process can be accelerated by environmental stress such as a rapidly heating climate.There were some interesting DNA changes, such as in areas linked to fat processing, that could help polar bears survive when food is scarce. Bears in warmer regions had more rough, plant-based diets compared with the fatty, seal-based diets of northern bears, and the DNA of south-eastern bears seemed to be adapting to this.Godden said: “We identified several genetic hotspots where these jumping genes were highly active, with some located in the protein-coding regions of the genome, suggesting that the bears are undergoing rapid, fundamental genetic changes as they adapt to their disappearing sea ice habitat.”The next step will be to look at other polar bear populations, of which there are 20 around the world, to see if similar changes are happening to their DNA.This research could help protect the bears from extinction. But the scientists said it was crucial to stop temperature rises accelerating by reducing the burning of fossil fuels.Godden said: “We cannot be complacent, this offers some hope but does not mean that polar bears are at any less risk of extinction. We still need to be doing everything we can to reduce global carbon emissions and slow temperature increases.”

A Deadly Pathogen Decimated Sunflower Sea Stars. Look Inside the Lab Working to Bring Them Back by Freezing and Thawing Their Larvae

For the first time, scientists have cryopreserved and revived the larvae of a sea star species. The breakthrough, made with the giant pink star, gives hope the technique could be repeated to save the imperiled predator

A Deadly Pathogen Decimated Sunflower Sea Stars. Look Inside the Lab Working to Bring Them Back by Freezing and Thawing Their Larvae For the first time, scientists have cryopreserved and revived the larvae of a sea star species. The breakthrough, made with the giant pink star, gives hope the technique could be repeated to save the imperiled predator Juvenile sunflower sea stars at the Sunflower Star Laboratory in Moss Landing, California. At this phase, each is less than an inch wide, but they can grow to be more than three feet across as adults. Avery Schuyler Nunn Key takeaways: Recovering sunflower sea stars by freezing them in time Ravaged by infectious bacteria, sunflower sea stars literally wasted away across the Pacific coast of North America—and their resulting population crash destabilized kelp forest ecosystems. Scientists pioneered a cryopreservation technique on the closely related giant pink star, raising hopes that a bank of frozen sunflower star larvae could one day be thawed in the same way and released into the wild. Along a working California harbor, where gulls wheel over weathered pilings and the old Western Flyer—the ship John Steinbeck once sailed to the Sea of Cortez—sits restored in its berth, researchers buzz about in a modest lab tucked between warehouses and boatyards. Inside, amid the hiss of pumps and the faint smell of brine from seawater tables, a scientist lifts a small vial from a plume of liquid nitrogen, its frosted casing holding the tiniest flicker of hope for a species on the brink. Each of the 18 vials contains between 500 and 700 larval giant pink sea stars. At this stage, they are tiny specks suspended in seawater, invisible to the naked eye. These particular larvae have been cryopreserved and stored at roughly minus 180 degrees Celsius since March. At the Sunflower Star Laboratory (SSL) in Moss Landing, California, scientists thawed the larval pink sea stars and coaxed them to successfully develop into juveniles this summer—a first for any sea star species. In October, the scientists thawed another batch of larvae from the same cohort to test larval growth and survival under different freezing conditions and thawing protocols. The breakthrough, however, isn’t really about the giant pink star, a species that’s common in the wild. Instead, these larvae serve as a crucial stand-in for the far more imperiled sunflower sea star (Pycnopodia helianthoides)—a vanishing species for which larvae are precious, limited and increasingly difficult to obtain. Perfecting cryopreservation methods on pink stars—ensuring they can survive freezing, resume feeding and grow into juveniles—lays the scientific groundwork for facilitating a return of Pycnopodia. The contents of a thawed vial are placed under a microscope to assess viability of the larvae. Avery Schuyler Nunn The discovery arrives at a precarious time, as sunflower stars have disappeared at a pace rarely seen in marine ecosystems. As a mysterious pathogen ravaged their population along the western shores of North America beginning in 2013, the creatures collapsed from an estimated six billion individuals to functional extinction in parts of their range—all within just a few years. Their loss left kelp forests with dramatically fewer predators, destabilizing ecosystems across the Pacific coast and allowing urchins to proliferate and graze formerly lush underwater canopies into barren rock. Now, scientists hope that “freezing” their larvae will offer a new avenue for bringing the species back. “Cryopreservation is particularly important on the population level when thinking about recovery for this endangered species, because it had major population losses,” says Marissa Baskett, an environmental scientist at the University of California, Davis, who was not involved in the project. The process lets scientists preserve the sea stars’ existing genetic diversity for future reintroduction to the wild, she adds. “Especially given the uncertainty about different disease outbreaks, having that stock to return to is incredibly valuable.” A mysterious and “complete collapse” Sunflower sea stars have long lived in abundance up and down the rugged Pacific coast—from Alaskan archipelagoes to Baja California. The 24-limbed echinoderms sprawled across the seafloor in shades of ochre, crimson and violet. Among the fastest-moving and largest of all sea stars—capable of stretching nearly three feet across—these radiant predators coursed through kelp forests, voraciously hunting purple sea urchins and preventing them from over-grazing on the holdfasts that root towering golden canopies of kelp. An adult sunflower sea star has 24 limbs and can be more than three feet wide. This one was photographed off Point Dume State Beach near Los Angeles. Brent Durand via Getty Images “In Northern California and Oregon, there historically would have been multiple keystone predators within the kelp forest ecosystem who are punching on purple urchins and keeping their population in check,” says Reuven Bank, board chair of SSL. “But the southern sea otter was extirpated across its historic range, so we were left with sunflower stars being the last major keystone predator of purple urchins across over 100 miles of coastline.” “And sunflower stars didn’t just eat urchins, they scared them,” Bank adds. “Urchins can smell a sunflower star approaching, and in healthy kelp forests they hide more and graze less. Even without consuming them, sunflower stars helped keep urchin behavior, and therefore kelp forests, in balance.” Then, in June 2013, tidepool monitors along Washington’s Olympic Peninsula documented an unprecedented sight. The once-sturdy sea stars had turned soft, pale and contorted, their arms curling and detaching from their bodies. By late summer, the same mysterious affliction had surfaced in British Columbia, and it began sweeping both north and south with startling speed. The emerging epidemic, which caused the invertebrates to literally disintegrate, would soon be known as sea star wasting disease. An infamous marine heatwave—nicknamed “The Blob”—had settled over the Pacific by 2014, thrusting the coast into a fever. Ocean temperatures spiked, likely speeding up the disease progression in already stressed sea stars and leading to higher mortality. In the warm, stagnant water, infected sunflower stars dissolved at an eerily rapid pace, leaving behind ghost-white films of bacterial mass where the vibrant predators had been just days before. “You’d have apparently healthy stars basically melt away into puddles of goo within 48 hours,” says Andrew Kim, lab manager at SSL. “It happened so quickly, and I don’t think folks were prepared for the ensuing ecosystem shift. You don’t often expect diseases to come through and totally reshape ecosystem dynamics within such a short period. But that’s what we saw.” Without sunflower sea stars to keep those spiny purple urchins in check, the balance began to falter, setting the stage for an unprecedented chain reaction. Urchin populations skyrocketed, grazing on kelp without limits, and once-thriving underwater forests collapsed into barren rock. A dense group of purple sea urchins, which exploded in population after the sunflower sea stars disappeared, photographed near Mendocino Headlands State Park, north of San Francisco. Brent Durand via Getty Images In California, with 99 percent loss, sunflower sea stars are now considered functionally extinct. “Even though there may be a few remnant individuals left, they can no longer fulfill their historic role in the ecosystem,” Bank says. As sunflower stars unraveled in the wild, another species—its thick-armed cousin, the giant pink star—offered an unexpected foothold for hope. The pink stars share a nearly identical geographic range and life history with sunflower stars, and crucially, their larvae can be raised in aquaria. If scientists could learn to freeze and revive the pink star in its early life stages, they wondered, could that knowledge become a lifeline for the sunflower star? That’s where the small team in Moss Landing stepped in. Freezing sea stars for the future What these scientists did was something no one had ever pulled off with a sea star. Working with giant pink stars, researchers spawned adults at the Aquarium of the Pacific in Long Beach, California, fertilized their gametes to produce thousands of larvae, and shipped those microscopic bodies to the Frozen Zoo—a cryopreserved archive of creatures operated by the San Diego Zoo Wildlife Alliance. There, reproductive scientists plunged the larvae into liquid nitrogen, cooling them to extremely low temperatures and pausing their cells’ biological activity. The larvae, essentially frozen in time, were shielded from ice crystal damage with special cryoprotectant mixtures. Sunflower Star Laboratory researchers remove a vial of pink star larvae from an insulated cooler at around minus 180 degrees Celsius in preparation for thawing. Avery Schuyler Nunn After months in this suspended state, the larvae were sent to the Sunflower Star Laboratory where Carly Young, a San Diego Zoo Wildlife Alliance scientist who advances cryopreservation and reproductive-rescue tools, led the team in thawing the vials. She had fine-tuned the ideal way to keep the larvae alive as they returned to real-world temperatures, carefully testing more than 100 “recipes” with various warming rates, cryoprotectant dilutions and rehydration steps. The pink star larvae not only survived thawing, but have thus far lived all the way through metamorphosis into juveniles. Scientists watched the little stars settle spontaneously along the bottom of their beakers just 19 days after revival. The success prompted the team to apply the same cryopreservation protocols to sunflower star larvae from the Alaska SeaLife Center. The larvae will be frozen in perpetuity, creating the first-ever cryopreserved archive of the species—like a seed bank, but for the baby sea stars. “A famous quote from the ’70s, when the Frozen Zoo in San Diego was established, was, ‘You must collect things for reasons you don’t yet understand,’” says Ashley Kidd, conservation project manager at SSL. “We don’t know when the other shoe is going to drop and what populations are going to look like as the planet changes. So, rather than chasing ghosts around the ocean floor, we really focused on what we can do with animals that are currently under human care somewhere.” While cryopreservation itself isn’t a ready-made restoration tool, it opens the door to conserving genetic diversity of a species and banking rare lineages for potential reintroduction to the wild. In the 1970s and 1990s, researchers began testing cryopreservation of marine invertebrates with sperm and larvae, establishing the basic protocols that this team could apply to sea stars. The breakthrough doesn’t restore kelp forests by itself, but the SSL scientists note that cryopreservation creates something the conservation community has desperately needed: time. Time to hold onto genetic diversity, time to refine captive rearing and time to prepare for future reintroduction at scales big enough to matter. The ultimate test, the researchers say, will be translating the thawing process to sunflower sea stars. Carly Young, at the Sunflower Star Laboratory, looks for movement in the young sea stars. Avery Schuyler Nunn Just this summer, scientists uncovered a piece of the puzzle that had eluded them for more than a decade: the pathogen behind sea star wasting disease. In a four-year international effort, researchers traced the outbreak to a strain of the marine bacterium Vibrio pectenicida. When cultured and injected into healthy sea stars, it reproduced the telltale symptoms—softening arms, rapid disintegration and death within days. The finding, published in Nature Ecology and Evolution in August, gives recovery teams a way to test for the pathogen in labs and hatcheries, tighten quarantine measures and understand disease risks before returning captive-bred sea stars to the Pacific. “It’s massively important to know what to look for, and the fact that we are now able to test for this disease is going to be critical in advancing our ability to move forward with reintroductions and continuing the research,” notes Kim. “We’ve already been able to take fluid samples from all of our stars and get them analyzed for the presence of Vibrio pectenicida, so we’ve mobilized very quickly on the heels of development.” Paired with this new diagnostic clarity, advances in cryopreservation offer a second front in the effort to save the species. Frozen larvae can be stored for decades and offer flexibility for selective breeding of disease-tolerant traits, notes the team. Cryopreservation adds another tool to the scientists’ toolbox as they fight to prevent the species—and, in turn, its ecosystem—from wasting away. “Bringing back sunflower stars,” Bank says, “is the single-most important step we can take toward restoring kelp forest balance.” Get the latest Science stories in your inbox.

Archaeologists Are Unraveling the Mysteries Behind Deep Pits Found Near Stonehenge

Based on a comprehensive study, researchers are now convinced the shafts were human-made, likely dug during the Late Neolithic period roughly 4,000 years ago

Archaeologists Are Unraveling the Mysteries Behind Deep Pits Found Near Stonehenge Based on a comprehensive study, researchers are now convinced the shafts were human-made, likely dug during the Late Neolithic period roughly 4,000 years ago Sarah Kuta - Daily Correspondent December 10, 2025 9:59 a.m. The pits are evenly spaced around a large circle. University of Bradford In 2020, archaeologists in the United Kingdom made a surprising discovery. At Durrington Walls, a large Neolithic henge not far from Stonehenge, they found more than a dozen large, deep pits buried under layers of loose clay. The pits are mysterious. Each one measures roughly 30 feet wide by 15 feet deep, and together they form a mile-wide circle around Durrington Walls and neighboring Woodhenge. They also appear to be linked with the much older Larkhill causewayed enclosure, built more than 1,000 years before Durrington Walls. For the last few years, archaeologists have been puzzling over their origins: Were they dug intentionally by human hands? Were they naturally occurring structures, like sinkholes? Or is there some other possible explanation for the existence of these colossal shafts? Quick fact: The purpose of Durrington Walls While Stonehenge is thought to have been a sacred place for ceremonies, Durrington Walls was a place where people actually lived. In a new paper published in the journal Internet Archaeology, archaeologists report that they have a much better understanding of the pits’ purpose, chronology and environmental setting. And, now, they are confident the shafts were made by humans. “They can’t be occurring naturally,” says lead author Vincent Gaffney, an archaeologist at the University of Bradford, to the Guardian’s Steven Morris. “It just can’t happen. We think we’ve nailed it.” Chris Gaffney, an archaeologist at the at the University of Bradford, surveys the ground near Durrington Walls. University of Bradford For the study, researchers returned to the site in southern England and used several different methods to further analyze the unusual structures. They used a technique known as electrical resistance tomography to calculate the pits’ depths, and radar and magnetometry to suss out their shapes. They also took core samples of the sediment, then ran the soil through a variety of tests. For instance, they used optically stimulated luminescence to determine the last time each layer of soil had been exposed to the sun. They also looked for traces of animal or plant DNA. Astonishing' Stonehenge discovery offers new insights into Neolithic ancestors. Together, the results of these analyses indicate humans must have been involved, which suggests the pits could be “one of the largest prehistoric structures in Britain, if not the largest,” Gaffney tells the BBC’s Sophie Parker. Researchers suspect the circle pits were created by people living at the site over a short period of time during the Late Neolithic period roughly 4,000 years ago. They were not “simply dug and abandoned” but, rather, appear to have been part of a “structured, monumental landscape that speaks to the complexity and sophistication of Neolithic society,” Gaffney says in a statement. For example, the pits are fairly evenly spaced around the circle, which suggests their Neolithic creators were measuring the distances between them somehow. “The skill and effort that must have been required to not only dig the pits, but also to place them so precisely within the landscape is a marvel,” says study co-author Richard Bates, a geophysicist at the University of St Andrews, in a statement. “When you consider that the pits are spread over such a large distance, the fact they are located in a near perfect circular pattern is quite remarkable.” Researchers used multiple methods to investigate the pits at Durrington Walls. University of Bradford But who dug the pits? And, perhaps more importantly, why? Archaeologists are still trying to definitively answer those questions, but they suspect the shafts were created to serve as some sort of sacred boundary around Durrington Walls. Their creators may also have been trying to connect with the underworld, per the Guardian. “They’re inscribing something about their cosmology, their belief systems, into the earth itself in a very dramatic way,” Gaddney tells the BBC. Get the latest stories in your inbox every weekday.

Is red meat bad for you? Limited research robs us of a clear answer.

We’d all appreciate more definitive guidance. Eating a varied diet is a wise move while we wait.

Over and over, we ask the question: Is Food X good or bad for you? And, over and over, belief in the answer — whether it’s yes or no — is held with conviction totally out of proportion with the strength of the evidence.Today’s illustration: red meat. It has become one of the most-disputed issues in food. It’s so polarizing that some people decide to eat no meat at all, while others decide to eat only meat. It’s poison, or it’s the only true fuel.The latest salvo in the Meat Wars was kicked off by a new report that outlines the optimal diet for both people and planet. The EAT-Lancet Report comes down hard on red meat; its recommended daily intake is a mere 14 grams — that’s half an ounce.Read on, and the news gets worse: “Because intake of red meat is not essential and appears to be linearly related to higher total mortality and risks of other health outcomes in populations that have consumed it for many years, the optimal intake may be zero.”Note that word: “related.” It’s the source of the problem with the report and its recommendation.The EAT-Lancet report, by researchers from 17 countries, bases its recommendation solely on observational data. When you do that, meat comes out looking pretty bad. In study after study, people who report eating a lot of meat have worse health outcomes than people who eat little. Meat-eating correlates with increased risk of heart disease, some cancers and all-cause mortality.But, as always with observational research that attempts to connect the dots between diet and health, the key question is whether the meat itself, or something else associated with a meat-heavy lifestyle, is actually causing the bad outcomes.That’s a hard question to answer, but there are clues that people who eat a lot of meat are very different from people who eat a little.Let’s look at a study, published in JAMA Internal Medicine, cited by the EAT-Lancet report; it has a convenient demographic summary. According to it, people in the top one-fifth of meat eaters are different from people in the bottom fifth in a lot of important ways: They weigh more, they’re more likely to smoke, they’re not as well-educated, they get less exercise, and they report lower intakes of fruit, vegetables and fiber. On the plus side, they report drinking less alcohol. But other than that, we’re looking at a litany of markers for a lifestyle that’s not particularly health-conscious.So, to suss out whether it’s the meat that’s raising disease risk, you have to somehow correct for any of the differences on that list — and most of that information also comes from observational research, so even the confounders are confounded.Then there are the things you can’t correct for. Sleep quality, depression and screen time, for example, all correlate with some of the same diseases meat correlates with, but most studies have no information on those.All this confounding explains one of my all-time favorite findings from observational research. It comes from the same study the demographics came from (analyzed in a 2015 paper). Sure enough, the people who ate the most meat were more likely to die of cancer and heart disease, but they were also more likely to die in accidents. And the biggest difference came from the catchall category “all others,” which invariably includes causes of death that have nothing to do with meat.Basically, there’s a very simple problem with relying on observational research: People who eat a lot of meat are very different from people who eat less of it. The meat definitely isn’t causing the accidental deaths (unless, perhaps, they’re tragic backyard grill mishaps), and it isn’t causing at least some of the “all others” deaths, so we know that heavy and light meat-eaters are different in all kinds of ways.That’s where controlled trials come in.In a perfect world, we could figure this out by keeping a large group of people captive for a lifetime, feeding half of them meat, and seeing what happens. Okay, maybe that’s not a perfect world, but it would be the best solution to this particular problem.Instead, we have trials that are short-term (because of logistics and cost), and necessarily rely on markers for disease, rather than the disease itself. For that to be useful, you need a marker that’s a reliable indicator. For a lot of diseases — including cancer — those are hard to come by. For heart disease, we have a good one: low-density lipoprotein (LDL) cholesterol. So, most of the controlled trials of meat-eating focus on heart disease.If you spend some time reading those trials (and I did, so you don’t have to), you find that most of them show some increase in LDL cholesterol, although it’s generally small.A 2025 analysis of 44 controlled trials on meat found that the only ones showing positive cardiovascular outcomes had links to the meat industry, and even then, only about one in five came out positive. Of the independent studies, about three-quarters showed negative outcomes, and the remaining one-quarter was neutral.This isn’t surprising. Red meat contains saturated fat, and we have countless trials that demonstrate sat fat’s ability to raise LDL. But if the meat you eat is relatively lean, that effect is going to be small.The lesson here is that we don’t have a lot of good evidence on meat and health. The observational evidence is hopelessly confounded, and the evidence from clinical trials is woefully limited. There’s so much we simply don’t know. There may be other ways meat raises risk (leading to over-absorption of heme iron and stimulating the production of TMAO, or trimethylamine N-oxide), but there’s little definitive evidence for them. And, of course, there’s the question of what you eat instead. If you’re eating red meat instead of, say, instant ramen, that may be an improvement. If, instead, you’re cutting back on your lentils, not so much.As always, the single-most important thing to remember about nutrition is that what we know is absolutely dwarfed by what we don’t know. Which means that, if you’re making decisions based on what we do know, you could very well be wrong.So what’s an eater to do? Meat is a nutritious food. In fact, animal foods are the only natural sources of a vitamin we need — B12 — which is an indication that we evolved with meat and dairy as part of our diet. It’s very hard to know whether eating some lean meat leads to better outcomes than eating no meat, but I think some meat is a good hedge against all that uncertainty. (The ethical and environmental concerns are also important, but for today let’s focus on health.)But plant foods are also nutritious. And eating a wide variety of them is also a good hedge against uncertainty. Which means the carnivore diet — all meat, all the time! — is a pretty bad bet.Unfortunately, “uncertainty” is not a word that features prominently in the Meat Wars. Instead, we have an unappetizing combination of nastiness and sanctimony, with each camp convinced that the truth and the light are on their side.Not that this is a metaphor for our times or anything.

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