While humans continue to dream of being immortal and living forever, there are animals that are technically immortal. That is, they can die at the hands of a predator, from an illness, or due to an injury. However, many of the creatures on this list do not die of old age; they can regenerate or “rewind” their lives. It is even quite possible that they would dominate the Earth if the rest of the species disappeared.
1. The Biologically Immortal Jellyfish
The Turritopsis dohrnii is known as the immortal jellyfish because, biologically, it can live forever. So far, it is the only known animal capable of completely reverting to sexual immaturity. For practical purposes, if one of these small jellyfish (they are very small) suffers an injury or falls ill, it can rebuild its cells and return to its earliest life phase within three days. If this species were conscious, it could continually “rewind” its life to avoid death.
2. The Elves of the Animal World
In fantasy fiction, elves often only die due to illness (physical or mental). That’s somewhat similar to what happens with lobsters: they keep growing and growing until they die of illness or serious injury. “So why don’t we see giant lobsters?” you might ask. Lobsters don’t have skin; they have an exoskeleton, and the bigger the exoskeleton, the harder it is to shed. When a large lobster suffers a serious injury, it becomes fatal if it can’t shed its exoskeleton in time.
3. Eternal Patience
As explained by The New York Times, like lobsters, turtles could live indefinitely if it weren’t for diseases and predators. Due to these factors (and the harmful impact humans have on their ecosystem), it is typical for a sea turtle to live about 80 years. However, there have been exceptions throughout history. For example, the oldest turtle in the world was born in 1832. His name is Jonathan, and he lives at his own leisurely pace on the island of Saint Helena.
4. A Miniature Hydra
Are you familiar with the myth of the hydra? A mythological creature that, if you cut off one head, grows two more in its place. There’s a miniature and much more peaceful version of this: the planarian worm. Like the jellyfish mentioned above, it can regenerate organs lost to a predator’s attack or after mating. And if someone were to cut it in half, each part would grow into a new planarian. Luckily, these worms aren’t interested in world domination.
5. The Mystery of the Bicentennial Whale
According to Popular Science, the life expectancy of a bowhead whale is around 70 years (they are the “oldest” mammals, excluding humans). However, a curious discovery occurred in the 1990s when scientists found a group of these whales with scars from weapons used in the 18th century. Since then, older bowhead whales have been identified, with the record held by one that is 211 years old. It’s still unknown how they can live so long, and scientists are unsure if this longevity is an anomaly or a rule yet to be understood.
6. The Bacterial Phoenix
The Deinococcus radiodurans is an extremophile bacterium considered one of the most resilient organisms on Earth. Much like a phoenix, if it “dies,” it can revive as though nothing happened due to its self-repairing DNA. In terms of resilience, it can withstand up to 1.5 million rads of gamma radiation, which is 3,000 times more than a human could endure.
7. The Creature That Will Inherit the Earth
If time machines existed and you could travel to a distant future where Earth has endured countless hardships, you would likely find only one surviving species: tardigrades (also known as water bears because of their appearance and movements). They can survive 10 years without water, endure pressures up to 6,000 atmospheres, withstand temperatures ranging from -200 to 150 degrees Celsius, and, like the bacteria mentioned above, tolerate high levels of radiation. Thankfully, they look quite adorable, so they seem like better candidates for Earth’s “absolute emperors” than the ever-surviving cockroach.
