For centuries, humans have searched for ways to slow ageing and extend life, possibly forever.
While we haven’t cracked the secret to immortality yet, nature might already hold the answers. Some creatures have evolved incredible abilities—regenerating lost body parts, defying ageing, or even resetting their biological clock entirely. Scientists are studying these unique species in the hopes of unlocking the secrets to longer, healthier lives. If we can understand how they work, we might one day apply their biological tricks to human medicine. Here are some of the creatures that could hold the key to helping us live forever.
1. The immortal jellyfish (Turritopsis dohrnii)
If any creature comes close to true immortality, it’s this tiny jellyfish. Unlike most animals, which age and eventually die, the immortal jellyfish can reverse its ageing process. When it experiences stress or injury, it transforms its adult cells back into their earliest stage of development and starts life over again.
Scientists are fascinated by this ability, known as transdifferentiation, because it could provide clues about reversing ageing in humans. If we could harness similar biological mechanisms, we might one day slow, stop, or even reverse the effects of ageing.
2. Planarian flatworms
Planarian flatworms take regeneration to another level. If you cut one in half, both halves will regrow into fully functioning worms. Even more astonishingly, their stem cells allow them to regenerate indefinitely, meaning they technically never have to die of old age.
Researchers are studying their remarkable regenerative abilities to understand how cells renew themselves. If we can unlock their secrets, it could revolutionize medicine by helping humans regenerate damaged organs or even reverse degenerative diseases.
3. Naked mole rats
Naked mole rats are some of the most unusual mammals on the planet. They don’t age in the same way other animals do, showing little to no signs of age-related decline. Even more impressively, they are highly resistant to cancer and can survive in low-oxygen environments.
Scientists believe their longevity is tied to unique genetic adaptations that protect their cells from damage. Studying how naked mole rats resist ageing and disease could lead to breakthroughs in extending human lifespan and preventing age-related illnesses.
4. Lobsters
Unlike most creatures, lobsters don’t show signs of ageing as they grow older. Thanks to an enzyme called telomerase, their cells can keep repairing themselves indefinitely, allowing them to continue growing and reproducing throughout their lives.
Humans also have telomerase, but it becomes less active with age. Understanding how lobsters maintain continuous cell renewal could help scientists find ways to slow or even halt human ageing without increasing the risk of diseases like cancer.
5. Hydras
Hydras are tiny freshwater organisms that seem to defy ageing. Their stem cells continuously regenerate, allowing them to maintain their youthful state indefinitely. As a result, hydras don’t experience the same kind of cellular decay that leads to ageing in other animals.
Researchers are especially interested in hydras because they show that ageing isn’t an unavoidable biological process. If scientists can figure out how to trigger similar regeneration in human cells, it could change how we approach ageing and medicine.
6. Greenland sharks
Greenland sharks are the longest-living vertebrates on the planet, with some individuals estimated to be over 500 years old. They grow incredibly slowly, sometimes taking over a century to reach maturity, and they show very little sign of ageing.
Scientists suspect that their longevity is linked to their slow metabolism and unique adaptations to extreme environments. Studying these ancient creatures could help uncover why some animals live dramatically longer than others, and how humans might extend their own lifespans.
7. Tardigrades
Also known as water bears, tardigrades are microscopic creatures that can survive some of the most extreme conditions imaginable. They can endure freezing temperatures, radiation, intense pressure, and even the vacuum of space.
The key to their survival lies in their ability to enter a state called cryptobiosis, in which they effectively shut down their metabolism until conditions improve. Understanding how tardigrades protect their cells and DNA could lead to medical breakthroughs in slowing ageing and increasing human resilience.
8. Sea urchins
Certain species of sea urchins appear to defy ageing. Instead of declining over time, they maintain their ability to regenerate damaged tissue and reproduce indefinitely. Scientists are studying their regenerative processes to learn how they maintain their youthful biology. If we can apply these insights to human medicine, it could pave the way for new treatments that prevent or reverse age-related deterioration.
9. Axolotls
These fascinating amphibians are famous for their incredible regenerative abilities. Unlike humans, they can regrow entire limbs, spinal cords, and even parts of their heart and brain without scarring.
Scientists are studying axolotl genetics to understand how they repair tissue so effectively. If we could replicate their ability to regenerate organs or nerves, it could revolutionize treatments for spinal cord injuries, amputations, and other major medical conditions.
10. Bowhead whales
Bowhead whales are the longest-living mammals, with lifespans exceeding 200 years. Unlike most large animals, they rarely develop cancer, which has sparked interest in how their genetics might protect them from age-related diseases.
Researchers are studying their DNA to understand how they resist ageing and disease. If humans can harness similar biological defences, it could lead to breakthroughs in preventing cancer and extending healthy lifespans.
11. Ocean quahogs
Ocean quahogs are a type of clam known for their extreme longevity. One individual, nicknamed “Ming,” was discovered to be over 500 years old. These creatures show very little cellular ageing, making them a key focus of longevity research.
Scientists believe their slow metabolism and resistance to oxidative stress contribute to their long lives. Understanding how their cells resist damage could offer insights into extending human health spans.
12. Glass sponges
Glass sponges are deep-sea creatures that grow slowly and can live for thousands of years. Some species are estimated to be over 10,000 years old, making them among the longest-living animals on Earth. Studying how their cells maintain function over millennia could reveal ways to slow tissue deterioration in humans. If we can unlock their biological secrets, it might help us combat ageing at a cellular level.
13. Rockfish
Certain species of rockfish can live over 200 years, far longer than most fish. Unlike other species, they age incredibly slowly and maintain their health for most of their lives. By analysing their genetics, scientists hope to identify the biological pathways that allow for extended lifespans. These findings could be key in understanding how humans might delay ageing and stay healthier for longer.
Nature has already figured out ways to extend life, regenerate organs, and slow down ageing. By studying these remarkable creatures, scientists are getting closer to understanding how we might one day apply these lessons to human health. While immortality may not be within reach just yet, these animals are helping us get one step closer to unlocking the secrets of longevity.
