At the top of our immortal animals list is a tiny variety of jellyfish known as Turritopsis doohmii, or more commonly, the immortal jellyfish. It has found a way to cheat death by actually reversing its aging process, according to National Geographic. If the jellyfish is injured or sick, it returns to its polyp stage over a three-day period, transforming its cells into a younger state that will eventually grow into adulthood all over again.
There is a debate among the scientific community whether these red ocean dwellers are biologically immortal animals; a common cause of death is disease, not old age, and unlike other animals, lobsters grow and reproduce until they die.
Turtles have been known to live for centuries, and researches have found that their organs don’t seem to break down over time. The New York Times reports that turtles might even be able to live indefinitely if they are able to avoid predators and disease.
These creepy crawlers, also known as planarian worms, are famous for their regeneration abilities, where a worm cut across or lengthwise can form two separate worms. This apparently limitless regeneration also applies to aging and damaged tissue, allowing the worms to cheat death indefinitely.
Though not technically immortal animals, the bowhead whale is the oldest living mammal. According to Popular Science, several species of whales have been known to live for more than 70 years. The oldest known bowhead lived to be 211 years old.
Deinococcus radiodurans, a poly-extremophilic bacterium, isn’t only radiation-resistant. These immortal animals can also die and come back to life thanks to their incredible DNA repair response. According to Ira S. Pastor, CEO of Bioquark Inc., “[They] can survive cold, dehydration, vacuum, and acid, and [have] been listed as the world’s toughest bacterium.” The Guinness Book of Records even says they “can resist 1.5 million rads of gamma radiation, about 3,000 times the amount that would kill a human!”
The most indestructible species on the planet – Tardigrade
Anything that tries to kill a tardigrade will quickly realize they encountered practically immortal animals. These creatures are capable of sticking around for thousands of years or even indefinitely “by entering a state of cryptobiosis, whereby their metabolism comes to a halt,”