When you think a person is old, just how old are they? Does 50 seem old? What about 75? Or 100? That may be old for a human being. But for a glass sponge, turning 100 would be like a person reaching their first half-birthday. Compared to many animals, people do live a long time. But we’re hardly alone — and we’re nowhere near the longest-lived animals on the planet.
The oldest person on record was Jeanne Louise Calment of France. She lived for 122 years. She was born the year before Alexander Graham Bell patented the telephone and died in 1997 — one year after the first flip phone came out. That’s a long life! As of 2019, the average human life expectancy was 73.1 years.
People have generally been living longer than they did just a few decades ago, thanks to greater access to medicines, clean water and other life-saving resources. A 2021 study found that humans could probably even live up to 150 years. It’s unlikely people will ever live longer than that, the scientists say, because our bodies must work to repair themselves. And by the time we reach 100 years old, it’s difficult for our cells to keep up.
Other animals can live way longer. How long depends on a variety of things, from body size to habitat. Let’s see how some zoological old-timers’ lifespans measure up, what allows them to age so well — and how they are spurring fascinating new discoveries.
Naked mole rats — up to 40 years
A mere 8 centimeters (3 inches) long, these critters are about the size of mice. But mice live for about two years (if they’re lucky). A naked mole rat, on the other hand, can live to be 40.
Being small often means having a short life, in part because other things want to eat you, says Juan Manuel Vazquez. He studies aging at the University of California, Berkeley. Since small animals are often prey for other animals, they have not evolved to have long lives.
What makes naked mole rats special? They live underground in large social groups, similar to what we see with honey bees and other social insects. Because they rarely pop their pink heads above ground, naked mole rats are hard for predators to nab. Without that pressure to grow up and reproduce quickly, they have evolved to live longer.
But living for decades means that naked mole rats must deal with other problems that shorter-lived creatures don’t. Diseases like cancer, for instance. A 2023 study found that these unusual rodents have high levels of anti-cancer compounds.
“They make a simple change to a common biomolecule” in their tissues, Vazquez says. The modified molecule starves cancer cells. And naked mole rats “become cancer-resistant as a result.”
Bats — more than 40 years
We know that bats can live to be at least 40, because the oldest known bat was caught 41 years after it was first tagged. It belonged to a species called Brandt’s bats, which are downright tiny. Each one weighs just 6 grams — about six large paper clips.
Not all bats live as long as Brandt’s bats. But even short-lived species survive 20 years — much longer than most similar-sized rodents. Bats seem to fly in the face of the small-animals-die-young trend. Why can they live so long?
Flying is one reason. Bats’ ability to take to the air when danger is near means they can avoid many predators. They find similar protection by roosting on the ceilings of caves or under bridges. Like naked mole rats, bats’ ability to avoid being eaten means they have not faced pressure to speed-run their lives. This has allowed them to evolve long lifespans.
The oldest bat on record was a Brandt’s bat like this one. These tiny fliers can live to be at least 40 years old.imageBROKER/Franz Christoph Robiller/Getty Images
But bats have more than flying to thank for their long lives, Vazquez says. Come winter, most bats hibernate. Those that don’t still enter a shorter deep sleep called torpor.
In both hibernation and torpor, the body slows down. Bats “don’t really need to breathe” during hibernation, Vazquez says. Air passively enters their lungs. And their “wings are so thin that air just naturally diffuses through those membranes.” As a result, bats “just kind of go into a state of suspended animation.” This allows the animals to save energy, which seems to help them live longer.
In 2022, biologist Isabel Sullivan, then at the University of Maryland in College Park, led a study of big brown bats. Northern populations age more slowly during hibernation and live longer than southern populations that don’t hibernate, her team found.
Do you have a science question? We can help!
Submit your question here, and we might answer it an upcoming issue of Science News Explores
Kākāpōs – up to 100 years
The kākāpō (KAHK-ah-po) might be the bird with the longest lifespan, although people aren’t quite sure how long these parrots can live. Kākāpōs are found only in New Zealand. Conservation scientists there think the birds might reach the ripe old age of 90 — or even over 100.
Kākāpōs are flightless birds. But they don’t have any ground-dwelling predators on the islands of New Zealand. A lack of predators helps boost the lifespans of these birds, similar to the way it does for mole rats and bats. Kākāpōs had predators in the past: two birds of prey that went extinct about 600 years ago. Losing those predators might have extended their lifespan.
Kākāpōs may owe their long lives to a lack of predators and slow metabolisms.
What’s more, not flying allows the kākāpō to have “a relatively slow metabolism for a bird,” says Lara Urban. “That might contribute to it living longer.” Urban is a genomicist at Helmholtz Munich in Neuherberg, Germany. A genomicist studies an organism’s full set of DNA. A slow metabolism leads to less damage to DNA, which causes cells to age slower.
Kākāpō are unusual for other reasons, too. They have owl-like faces and exist in two color variations: bright green and olive. Both colors help them blend into their forest habitat. But scientists didn’t know why the two colors exist. Typically, if one color helps an animal survive or find mates, that color becomes the only one in the population.
A recent study led by Urban found that kākāpōs’ ancient predators, which hunted by sight, drove kākāpōs to develop two colors. Predatory birds would focus first on kākāpōs of one color. They’d find and eat those birds until they became less common, Urban explains. Then predators would focus on the other color. This switching kept both colors in the population, even long after the hunters were gone.
Giant tortoises play an important role in maintaining their forest habitats on tropical islands.Katiekk2/iStock/Getty Images Plus
Giant tortoises — up to 200 years
Most giant tortoises live well over 100 years, but one is nearing the 200 mark. Jonathan, a Seychelles giant tortoise, is at least 192 years old. He was given, fully grown, to the governor of St. Helena in 1882. (St. Helena is a remote tropical island in the south Atlantic.) Now, 31 governors later, Jonathan is still wandering the grounds of the governor’s plantation.
What helps tortoises live such long lives? For one thing, their metabolisms, like the animals themselves, run slow. And like many reptiles, giant tortoises are ectotherms. That means they don’t spend their own energy to keep their body warm, the way mammals do. Instead, they rely on external sources of warmth, like the sun.
Add in a strong, protective shell and large size, and there aren’t many predators that can eat tortoises. Those traits allow these animals to win the race against time — as long as people let them be.
The island nation of Madagascar, off the eastern coast of Africa, was once forested and home to many giant tortoises. But people hunted them. And they burned down forested areas, whose shade tortoises relied on to stay cool.
Helping that forest recover hasn’t been easy. But a 2024 study found giant tortoises can play a critical role by spreading tree seeds. By dropping seeds in pats of poop, the reptiles also make it more likely the seeds will begin to grow — helping restore their own ecosystems.
A bowhead whale surfaces to breathe in cold Arctic waters near Russia.wildestanimal/Moment/Getty Images
Bowhead whales — 200 years
Most of the longest-lived animals live in the ocean. There’s evidence that the biggest — great whales — may all be old-timers if they can avoid encounters with people. One in particular, the bowhead whale, holds the record for longest-lived mammal.
Bowheads live in icy Arctic waters. Cold temperatures tend to slow metabolism and extend lifespan. But these whales also have anti-cancer genes to keep them healthy.
Large animals like whales have more skin than small animals do. When they’re growing, they need to form new skin cells all the time. But once a whale is grown, it only needs new skin after a shark bite or other injury. So adult whales switch off genes in their DNA that promote skin growth. They switch on genes that help keep skin cells from growing out of control, which would cause cancer. “It’s like the emergency brake on the car,” Vazquez explains.
Bowhead whales seem to spend their long lives in good company. A 2024 study found that some bowheads appear to synchronize their diving even when they are more than 100 kilometers (60 miles) apart.
Evgeny Podolskiy, a marine geophysicist at Hokkaido University in Japan, led the study. “Whales might form a so-called ‘acoustic herd’,” he says. That is, “seemingly lonely animals are never alone.” Rather, they make up “a vast network of individuals interacting over vast ocean distances.”
Scientists are just starting to uncover the secrets of deep-sea Greenland sharks.Hemming1952/Wikimedia Commons (CC BY-SA 4.0)
Greenland sharks — 400 years
Like bowheads, Greenland sharks live in cold north Atlantic and Arctic waters. Unlike whales, which spend most of their time near the surface, these sharks stay in the deep sea. They can live for centuries. We know this because scientists have used radiocarbon dating on these long-lived fish.
One reason for Greenland sharks’ long lives is their remote location. This keeps them away from ships, fishing gear and other potential dangers. Another reason is that they conserve energy, swimming at a leisurely 1 meter (3 feet) per second.
Greenland sharks grow very slowly, taking hundreds of years to reach their large adult size. Fully grown, they measure more than 5 meters (16 feet) long. But, like bowhead whales, they have lots of genes that keep them healthy.
A recent study of Greenland shark DNA found dozens of genes that help repair DNA or prevent age-related disease, such as cancer. People have these genes, too, Vazquez points out. But Greenland sharks and bowhead whales have many more copies of them.
“Having more copies means you have a lot of spare tires in case something goes wrong,” he says. Long-lived animals have more time to gain harmful mutations in their DNA. All those extra copies of repair genes help keep such mutations from spreading.
Ocean quahog clams — 500 years
The oldest known ocean quahog (KOH-hog) reached 507 years old. Researchers collected it off the Icelandic ice shelf in 2006. We know its age because clams add annual rings to their shells, like trees add rings to their trunks.
Clams aren’t the most active animals, although their young larvae swim freely through the water until they find a good place to settle. Young clams are a popular food for lots of ocean animals. But once they grow big enough, clams can burrow into the ocean floor and close up their shells to stay safe.
These animals also burrow to keep cool. Ocean quahogs do best at 15° Celsius (60° Fahrenheit) or colder. And it seems that warm water poses a threat to their longevity.
Biologist Alyssa LeClaire works with the U.S. National Oceanic and Atmospheric Administration in Beaufort, N.C. She led a 2023 study of ocean quahog clams. In some parts of the ocean, young clams became much less common starting 120 years ago. This is probably due to warmer water from climate change. Older clams could protect themselves from too-warm water by burrowing deep into the seafloor. Young clams couldn’t escape hot water, so many of them died, leaving only the older clams in the population.
Black coral — 4,000 years
The oldest known black coral colony was more than 4,000 years old when collected.
Unlike hard, stony corals, black corals build their skeletons from chitin — the same stuff that makes up insects’ exoskeletons. Thousands of tiny animals called polyps build and share a coral colony’s tree-like skeleton. They add annual layers to the skeleton, much like tree rings. Dense forests of black corals create essential habitats for thousands of marine animals, including fish, squat lobsters and sharks.
Black corals live in all the world’s oceans. They can be found in shallow waters or up to 8.3 kilometers (5.2 miles) below the surface. Those that live in the coldest, deepest waters can live for millennia. Like Greenland sharks, this is likely due to the cold temps and remote location.
Despite this, black corals are threatened. They’re slow to grow and take a long time to reproduce. Their chitin skeleton polishes into beautiful pieces used in jewelry, so people often harvest them.
In 2024, a research group set out to study black coral reproduction. Understanding how they reproduce can help to protect dwindling populations. The team found that some black coral colonies are female and release only eggs. Some are male and release only sperm. When those cells meet, they can spawn new colonies. But some colonies change sexes from one breeding season to the next!
Glass sponge — 17,000 years
Without question, the oldest living animals on record are glass sponges. One deep-sea species, Monorhaphis chuni, was aged at 17,000 years. Scientists can figure out a sponge’s age by measuring how quickly these animals grow. They can then use that growth speed to calculate how long it must have taken living sponges to grow to their current size.
Like other long-lived marine animals, glass sponges live in cold waters, so they grow slowly. And “they live at great depths that are very stable environments,” says Andrzej Pisera. He is a paleobiologist who studies sponges at the Polish Academy of Sciences in Warsaw. Without the risk of predators or big waves, there aren’t many things around to kill glass sponges.
Sponges might not seem like animals, but they are — and they must eat to survive. To do so, they filter tiny pieces of food out of the water by creating a current. They move water through openings, which draws food inside the sponge.
The sponges spend their long lives anchored to the ocean floor with a single glass piece of its skeleton, or spicule. This anchoring, or basal, spicule is just 1 centimeter (0.4 inch) wide. But it can grow to be 3 meters (10 feet) long. That’s enormous for a spicule. Most are just a few millimeters long, Pisera says.
The basal spicule raises the sponge up off the seafloor, which helps it filter food from the water. In a 2021 study, Pisera found that these sponges arrange layers of silica in very specific ways to build a strong spike that holds them in place for thousands of years.
Can we all live longer?
“Aging is something that’s kind of fundamental to life itself,” Vazquez says. Organisms are born, grow up, grow old and eventually die. For people, age-related diseases like heart disease, diabetes and cancer play a big role.
But aging isn’t “an unsolvable, insurmountable problem,” Vazquez says. We have already overcome many diseases that used to shorten lifespan, he notes. Soon, diseases that are common in modern people might be cured too.
We aren’t anywhere near “curing” aging. And many people may not want to live to be 100 anyway. But almost everyone would like to have the health and energy of a 20-year-old while in their 80s. Scientists, including Vazquez, are working on making that a reality. They’re looking into the best diets for long-term health and developing new drugs for diseases. It’s “about making sure that we’re as healthy and fit as possible for the greatest proportion of our life,” he notes.
“I don’t believe aging is going to be cured in my lifespan,” he says. But he hopes that his kids or grandkids might live in a time when they don’t know what Alzheimer’s disease is. Or even some kinds of cancer. People may one day live longer, healthier lives — maybe even join the ranks of zoological old-timers.
