The genetic secrets that help some animals defy aging (Part 2 of 3)

By Leslie Alan Horvitz

Bats

“If we lived as long as bats, adjusted for size, we could live 240 years,” said Gerald Wilkinson, a biology professor at the University of Maryland and the lead author of a 2019 paper about bat longevity. In one case, a small bat, approximately one-third the size of a mouse, was recaptured, still healthy, 41 years after it was initially banded. Bats live longer than mammals of similar size that live on land. There are some 1,400 different types of bats. Not surprisingly, they have different food preferences—flying insects, fruits and nectar, fish and small crustaceans such as scorpions, and blood, which is the sustenance of vampire bats.

Some species can fly at speeds of up to 100 miles per hour, making them the fastest mammals on earth. But what has particularly caught researchers’ attention is their tendency to live in large colonies, where they’re exposed to deadly viruses, including rabies, Ebola, Marburg, Nipah, and Hendra, as well as other pathogens. (Bats are believed to have originated viruses such as COVID-19, and two related strains—SARS (Severe Acute Respiratory Syndrome) and MERS (Middle East Respiratory Syndrome), all of which can cause suffering and death in humans.)

Why do bats live so long—30 to 40 years is typical—when they are practically swimming in all these viruses? Bats, it turns out, have a remarkably robust response to viruses. Although scientists have inoculated them with lethal viruses, they exhibit minimal responses, showing no overt symptoms and developing only subclinical infections. Genomic sequences show that bats have an extraordinary innate immunity to viruses and inflammation. This immunity may contribute to their long lives.

Cockatoos

In captivity, a cockatoo, a type of parrot, can generally live for 60 to 70 years. The oldest confirmed bird in captivity was a pink cockatoo named Cookie, who lived to 83. Another famous cockatoo in captivity, named Cocky Bennett, was said to have lived to the age of 119, though this is unconfirmed. In the wild, a sulfur-crested cockatoo typically lives for 40 years, but other cockatoo species—there are 21—may live longer. To explain why cockatoos and other parrot species live as long as they do, whether in captivity or in the wild, researchers at the Max Planck Institute examined two hypotheses.

One question was whether the larger brain size of birds, such as cockatoos, is responsible for their longer lifespans. Because in the wild, more intelligent birds can solve problems more effectively, they tend to live longer. The second was whether their relatively large brains simply take longer to grow, naturally resulting in longer lifespans. The results supported the first hypothesis. Parrots with relatively large brains possessed cognitive capabilities that enabled them to solve problems in the wild that could otherwise have led to their demise. Their intelligence enabled them to live longer lives. The scientists were surprised to find that other factors, such as diet or the longer developmental time required to develop larger brains, had no impact on their longer average lifespans.

Albatrosses

Most albatrosses live to age 50. The oldest wild albatross on record is Wisdom, a female Laysan albatross, estimated to be approximately 72 or 73 years old as of 2024. Researchers first tagged her in 1956, and she was estimated to have hatched around 1951. She has racked up three million miles in her travels around the world since 1956.

One theory to explain the longevity of albatrosses—applicable to other migratory birds as well—focuses on their power of flight. Annual migrations can take these birds thousands of miles, requiring them to remember geographic locations, maintain strong muscles, and keep their eyes and ears in a state of readiness. That means that they can more easily evade predators and find shelter. “They’ve had to be so highly engineered to succeed at flight,” says Steven Austad, who studies aging at the University of Birmingham. “That kind of physiological integrity has allowed them to stay healthy much longer than another animal.” Reproductive success may also account for longevity. In albatrosses and other long-lived seabirds, reproductive success actually increases with age. Wisdom, for example, has hatched 30 to 36 chicks with her mate (albatrosses are monogamous); that is, they have produced at least one chick per year since 2006.

Macaws

Like albatrosses, macaws (which belong to the parrot family) mate for life. They can survive for up to 60 years in the wild and 100 years in captivity. The oldest macaw in captivity lived to be 112 years old. Researchers have found that, as in other parrots, brain size plays a significant role in their longevity. “Large-brained birds might spend more time socially learning foraging techniques that have been around for multiple generations,” says Simeon Smeele, a doctoral student at the Max Planck Institute of Animal Behavior. “This increased learning period could potentially also explain the longer life spans, as it takes more time but also makes the foraging repertoire more adaptive.”

Tuataras

These lizard-like animals are the largest reptiles in New Zealand, and have one of the slowest growth rates of all reptiles, which may help to explain why they can live up to 100 years. They are sometimes referred to as “living fossils,” since they have no extant relatives. Although they share some traits with snakes, they diverged from them 250 million years ago, making them older than the oldest dinosaurs. They are close to impervious to many infectious diseases and demonstrate peak physical activity at shockingly low temperatures for a reptile. Tuataras have the lowest known optimal body temperature of any reptile, ranging from 16 to 21 degrees Celsius (or 60 to 70 degrees Fahrenheit).

Scientists interested in understanding why tuataras live so long have undertaken the first-ever deciphering, or sequencing, of their genetic code. They have found that the animal’s genome is enormous, about five gigabytes, or some five billion DNA base pairs in length, which is about two-thirds bigger than humans’ and is “unusually large” for a reptile. Many of these genes encode selenoproteins, which help protect against aging and cellular deterioration. Tuataras also appear to have an unusually high number of TRP genes, which encode proteins involved in temperature sensitivity and body temperature regulation. This may be why they can tolerate such low temperatures.

Giant tortoises

All tortoises are turtles, but not all turtles are tortoises. Turtles can live only in water, whereas tortoises can live on land, including deserts, grasslands, and wet tropical forests. And although turtles have an average lifespan of 40 years, the Galápagos tortoise—the largest species—can live up to 177 years in captivity, possibly longer. One giant tortoise, called Jonathan, is believed to have been born in 1832 and is alive and well in 2025. The Galápagos tortoise’s name is derived from the Spanish galápago, meaning “tortoise.” Some of the observations that led Charles Darwin to develop his theory of evolution were based on tortoises in the Galápagos Islands during the second voyage of the Beagle in 1835.

Giant tortoises can weigh up to 1,000 pounds. Like other large species, their metabolisms are set at an extremely low level, and their life stages tend to be comparably extended, as it takes them up to 30 years to reach sexual maturity (about twice the time of a human). Animals with lower heart rates tend to live longer than those with higher heart rates. Giant tortoises have a heart rate of approximately 10 beats per minute. Humans have heart rates between 60 and 100 beats per minute, while the pygmy shrew, whose heart rate is 1,200 beats per minute (the fastest rate of any animal), survives for only a few months.

For longevity, several other factors work in the giant tortoises’ favor, including genetic traits related to DNA repair, immune response, and cancer suppression. One study found that tortoises have extra copies of genes (called “duplications”) that may protect against the ravages of aging, including cancer. Giant tortoises can destroy precancerous cells through a process called apoptosis. Cancer is more prevalent as species age, and a defense against cancer may help tortoises to become centenarians more often. In addition, because these larger species have more cells, they have a greater number of cells that are vulnerable to cancer.

Cave salamanders

These blind amphibians can regularly live to be 100 years old. They don’t appear to be resilient; they are pale, eyeless, and about a foot long. As their name suggests, they spend their entire lives in caves (in Southern Europe), where, of course, there is little need for vision. This creature, like most other long-lived species, has an unusually sluggish metabolism. It takes 15 years to mature, mate, and lay its eggs (every 12 years or so). Cave salamanders barely move except to seek food, not that they need much food. They have virtually no predators, and their ability to conserve energy also helps explain their remarkable longevity. For comparison, the next longest-lived amphibian, the Japanese giant salamander, only rarely lives to 50 years.

Glass sponges

These sponges, believed to be the oldest animals on Earth, also have one of the planet’s longest lifespans—more than 10,000 years, possibly 15,000 years. One glass sponge observed by researchers in the Ross Sea, a bay of Antarctica, is thought to be the oldest living animal on the planet. Glass sponges are composed of large, complex, glass-like skeletons made of silica; they spend their lives attached to hard surfaces, filtering water through thousands of holes to consume bacteria and plankton. The filtration is also fast—80,000 liters per second. They also serve as habitats for small crustaceans. The relative simplicity of their structure may explain why these sponges live so long. Glass sponges are among the organisms often classified as biologically immortal, as their cells can regenerate infinitely, thereby preventing biological aging. However, “immortal” is a bit hyperbolic, as these animals are still vulnerable to predation, disease, and environmental changes.

Giant barrel sponge

Another sea sponge, the barrel sponge, is the largest species of any sponge and is found in the Caribbean Sea. It may be more than 2,300 years old, earning its nickname the “redwood of the reef” due to its large size and long lifespan. It typically grows in Caribbean coral reefs at depths up to 390 feet (120 meters). It is usually large, firm, and cone-shaped, although some varieties are low and squat. However, why it lives so long remains a mystery. One clue may come from research conducted in 2025, which proposed that the environment may be a significant factor in its longevity. The sponges, the researchers say, may be resilient to the effects of sediment by producing mucous. The mucous, in turn, removes the sediment from the surface of these ‘redwoods of the reef,’ which may allow the sponges to resist environmental conditions that would inhibit their ability to thrive and survive for millennia.

Black coral

Corals are among the longest-living animals on Earth. Some coral species can live up to 5,000 years, but black corals in the genus Leiopathes are known to be the longest-living of all corals. It takes considerable time to create an entire coral reef; therefore, coral formations grow an average of only 1 to 1.5 inches per year. Corals are constructed out of colonies, which in turn are formed by individual polyps, some of which may have lifespans of a few hundred years, whereas some polyps may only live for a couple of years. Corals, which depend on sunlight and salt to grow, are generally found in clear, shallow saltwater. They require warm temperatures—no more than 70 degrees Fahrenheit—and are susceptible to pollution.

Ocean quahog

This mollusk can live up to 500 years and is found in the North Atlantic from Newfoundland to North Carolina. Like so many long-lived species, it grows very slowly, reaching reproductive maturity only at the age of six. Biologists have yet to figure out why quahogs live so long. However, they suspect that its relatively stable antioxidant levels help to prevent the cell damage responsible for most signs of aging in animals.

(Leslie Alan Horvitz is an author and journalist specializing in science and is a contributor to the Observatory. His nonfiction books include Eureka: Scientific Breakthroughs That Changed the World, Understanding Depression with Dr. Raymond DePaulo of Johns Hopkins University, and The Essential Book of Weather Lore. His articles have been published by Travel and Leisure, Scholastic, Washington Times, and Insight on the News, among others. Leslie has served on the board of Art Omi and is a member of PEN America. He is based in New York City. Find him online at lesliehorvitz.com. This article was produced for the Observatory by the Independent Media Institute.)