Buzz
One of humanity's deepest desires is to live free from the concerns of aging. Stories of magical fountains and mythical places of eternal life have been passed down in our legends and fairy tales. Yet, time marches on for each of us, leading us inevitably toward the end. Still, the dream of something different persists.
As a rather cruel twist, we can look at certain creatures on Earth and discover they possess what we long for. These animals are sometimes mistakenly labeled as biologically immortal. While they are not immune to death, their difference lies in the fact that they never undergo the aging process like we do. They maintain their youthful vitality until something else takes their lives.
Here are 10 animals that defy the aging process or can stop it altogether.
10. Marine Sponges
When it comes to multicellular animals, marine sponges are among the simplest. They lack many of the features common in more complex animals, like ourselves. No internal organs, digestive systems, or even nervous and muscular systems are present.
However, a marine sponge has been discovered to be over 11,000 years old, with some research indicating that these creatures could live for hundreds of thousands of years. Their longevity might be attributed to their astonishing simplicity.
Biologists Andrey Lavrov and Igor Kosevich, who examined the remarkable abilities of marine sponges, found that when the sponges were subjected to tissue dissociation (by either mechanical or chemical methods that separate the cells), they could reconstruct themselves into their original form.
The biologists noted, “In several instances, such multicellular aggregates may lead to the complete regeneration of an animal’s original structure.” These extraordinary regenerative powers make these creatures nearly immortal.
9. Planaria (Flatworm)
Our education introduced us to the remarkable regenerative abilities of flatworms—simple creatures capable of regenerating into two fully functional flatworms when split in half. Recently, a lab at MIT demonstrated the ability to regenerate an entire flatworm from just a single cell. However, one key element of this extraordinary ability may not have been highlighted in our school lessons.
Dr. Aziz Aboobaker from The University of Nottingham explained:
Typically, when stem cells divide—whether to heal wounds, reproduce, or support growth—they start to exhibit signs of aging. This means that stem cells eventually lose the ability to divide, reducing their capacity to replace aging specialized cells in our tissues. [ . . . ] However, planarian worms and their stem cells manage to bypass the aging process, continuing to divide and regenerate indefinitely.
Thanks to their cellular youth, flatworms resist the effects of aging, making it nearly impossible to accurately determine their lifespan.
8. Bdelloid Rotifers
These tiny creatures, typically no larger than 1 millimeter (0.04 in), can be found in bodies of water around the globe, as well as in environments like mosses and lichen. Although their typical lifespan is about 30 days, which doesn’t sound like immortality, they still deserve a spot on this list. Why?
These microscopic beings have an extraordinary ability to halt their bodily functions in times of crisis, such as during starvation or dehydration, effectively pausing their aging process. In fact, this period of dormancy can extend far beyond their normal lifespan.
Certain bdelloid rotifers have been known to survive up to 40 days without food, then resume their normal life cycles as though the 40-day period had never occurred. This scenario is akin to discovering humans who could go without food for 100 years, without aging a single day. Once they had access to food again, they would continue aging from where they left off and live a typical life thereafter.
7. Hydra
This creature, standing at only 2.5 centimeters (1 in) tall, resembles a small tree. To appreciate its place on this list, we must first grasp the idea of senescence— the phenomenon where the likelihood of death increases as an organism grows older.
For instance, as humans age, our chances of dying increase. However, the Hydra does not follow this trend. (Well, except for one species, Hydra oligactis. Tough luck, buddy.)
The Hydra achieves this remarkable feat by utilizing three distinct types of stem cells, which remain undifferentiated and have the potential to become a variety of specialized cells. These stem cells are continuously renewing the Hydra's body, thus preventing the aging process that would typically lead to increased mortality.
In laboratory conditions, it’s estimated that up to 5 percent of Hydra could live as long as 1,400 years using this regenerative process.
6. Ocean Quahog Clam
This marine bivalve mollusk stands out for the ease with which its age can be determined. Similar to a tree, its lifespan is recorded in the growth rings of its shell. Additionally, these rings provide insight into its life—wide rings indicate years of abundant food, while narrow rings signal periods of scarcity.
Because of this unique characteristic, one ocean quahog was determined to be 507 years old, making it the oldest of its kind ever discovered. This would place its birth year around 1499.
The key to the quahog's impressive longevity lies in its remarkably low production of reactive oxygen species—unstable oxygen molecules, also known as free radicals. Accumulation of these molecules can damage DNA, RNA, and proteins, ultimately leading to cell death.
Because the quahog produces fewer reactive oxygen species, it is better equipped to combat a common cause of aging, allowing it to live for many centuries. The 507-year-old quahog, named Ming, met its unfortunate end only because it was frozen after being captured, enabling researchers to accurately determine its age. Had it not been for this intervention, it likely would have lived much longer.
5. Lobster
Often caught as delicacies, these bottom-dwelling ocean creatures exhibit indeterminate growth, meaning they have no maximum size. This results in continuous growth as long as the lobster lives, with no biological process to stop it.
The heaviest lobster ever recorded weighed just over 20 kilograms (44 lbs) and was discovered off the coast of Nova Scotia. Lobsters typically live anywhere from 50 to 100 years, which isn’t too different from human lifespans. What makes lobsters particularly intriguing, however, is the way they age and die. Despite getting older, they show no decrease in appetite, libido, energy, or metabolism.
However, determining the age of lobsters is tricky. They grow by molting, a process where they shed their entire exoskeleton. After each molt, all the hard outer parts are discarded, leaving no measurable remnants to determine their age accurately.
It’s the molting process that eventually leads to their death, not the typical aging process humans experience. As lobsters grow larger, the risks of molting increase, and the energy required for it becomes greater.
Eventually, a large lobster will no longer have the energy to survive the molting process or even begin it, due to its massive size. If this limitation were somehow overcome, there’s no telling how long these creatures could live.
4. Midland Painted Turtle
While many turtles are known for their long lifespans and resistance to senescence, Blanding’s turtles and midland painted turtles exhibit an intriguing twist in aging. Elderly females not only lay more eggs than younger ones, but they also experience a significantly lower mortality rate, becoming more likely to thrive as they age.
The turtle family is famous for its impressive longevity. One giant tortoise, for example, lived to at least 250 years in the Calcutta zoo. Dr. Christopher J. Raxworthy of the American Museum of Natural History explained succinctly, 'Turtles don’t really die of old age.' In fact, the internal organs of older turtles are virtually identical to those of their youthful counterparts.
This remarkable lifespan is also reflected in how slowly female turtles reach sexual maturity, sometimes taking as long as 40 to 50 years in certain species. Dr. Raxworthy further stated that, aside from being struck by a vehicle or succumbing to a disease, turtles could potentially live forever.
3. Pando Tree Colony
Its name, which translates to 'I spread' in Latin, has earned it the nickname 'the trembling giant.' This extraordinary organism defies conventional expectations. It's a grove of quaking aspens, so named because the leaves make a distinct sound at even the slightest breeze.
Pando is a colony of trees sprawling over 100 acres, and every tree in this grove is part of the same organism. Quaking aspens primarily reproduce by sending out new trees from an existing root system, meaning that many trunks can emerge from a single organism.
Pando boasts 47,000 trunks. While individual trunks last around 100 to 150 years, Pando as a whole is estimated to be at least 80,000 years old, with some estimates suggesting it could be as old as one million years. This enduring grove ranks among the oldest and largest living organisms on Earth, weighing approximately 6 million kilograms (13 million pounds).
2. Bristlecone Pine Trees
These gnarly and twisted trees may not seem eternal. Their age is reflected in their gnarled appearance, with branches winding in on themselves like the skeletal fingers of an elderly person.
However, within them is a life form of extraordinary resilience. The bristlecone pine doesn’t measure its existence in centuries but in millennia. The oldest one known is believed to be over 5,000 years old.
The precise location of this ancient tree and other notably old bristlecone pines is kept hidden to protect them from potential harm, whether intentional or accidental. Another bristlecone pine, known as Prometheus, which was just shy of 5,000 years old, was felled in the same area.
The wood of this pine is both dense and resinous, providing it with natural protection against threats like fungi and insects. Even after the tree dies, its form remains sturdy for centuries, upheld by its roots.
1. Turritopsis Dohrnii (Jellyfish)
Imagine being able to reverse aging whenever we choose. Our hair would regain its youthful color, wrinkles would vanish, our bodies would become stronger, and our metabolism would speed up. We’d feel like teenagers, then children, and eventually like babies once more.
Then, we’d begin aging again from the start, living our lives a second time, none the worse for wear. This is the reality of the Turritopsis dohrnii, the immortal jellyfish. At any stage of its life, this jellyfish can reverse aging through a process called transdifferentiation, reverting to its youngest form and continuing its life from there. As far as we know, this process can continue indefinitely.
This process can be initiated by various factors, ranging from injury to aging, hunger, or illness. If undisturbed, these jellyfish will undergo rejuvenation about ten times within a two-year period.
At times, these events occur in less than a month’s time. Additionally, this eternal jellyfish is an adept traveler, having spread across the globe’s oceans by hitching rides on cargo ships.
