ExtinctZoo - The Most Impossible Animals Ever Discovered

Episode Date: July 30, 2025

Immortality, wouldn't it be nice? Well, for some animals out there, they don't actually have to wonder, as thanks to some nifty evolution, they have in some ways figured out how to beat death!

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Terms apply. Death is supposed to be the one universal constant, the ultimate equalizer that every living thing on Earth has to face. But as it turns out, some animals apparently didn't get the memo. While the rest of us are busy aging, deteriorating, and slowly falling apart, there are animals out there that have essentially told death to take a hike. And no, this isn't some fantasy novel creatures, but rather real animals that are breathing, swimming, and crawling around on earth right at this moment, just somehow at the same time,

seemingly ignoring nature's rulebook. Now, most life follows a pretty predictable script. You're born, you grow up, you probably pay taxes, reproduce, and then your body slowly starts falling apart, like a car that's been driven too hard for too long. And scientists call this delightful process senescence, which is just a polite way of saying that your body is slowly giving up on you. Muscles weaken, parts wear out, errors stack up in our cells, DNA frays, organs lose their edge, knees pop, back hurts, hangovers get worse, and the list goes on. And once this lovely process starts, it doesn't stop. Well, at least until you're six feet under. But

But here's where things get interesting. This is just how it works for us mere mortals. It's a handful of species have figured out ways to bend, break, or even completely ignore these rules. They have achieved what scientists hintably refer to as biological immortality. Not the kind where you can't be killed, but rather the kind where it's just very hard to die, essentially having solved many of the problems of aging, and basically being the biological equivalent of finding a cheat code for the game of life.

But who are these lucky creatures, you may ask? Well, some you probably never even heard of, let alone seen, but others you may surprisingly have met, and perhaps even eaten, such as our friend, the American Lobster. These armored crustaceans have pulled off one of nature's most impressive feats by essentially solving the worst part about aging, you know, the whole getting slower, weaker, and a, less rambunctious. Throughout their entire lives, they pump out massive amounts of something called telomerase, which is an enzyme that protects chromosomes from the usual fraying and damage that

comes with time, and it does this by helping to maintain the length of telomeres, the protective caps at the end of each chromosome. And this massive amount of telomerase production helps keep their cells not only functionally young, but their fertility high. In other words, a 100-year-old lobster is just as strong, healthy, and fertile as a 10-year-old one. In fact, not only is the 100-year-old just as fertile, they are possibly even more fertile than their young and supposedly limber counterparts. Would be nice. And telomerase doesn't just make their cells young and healthy, but it also keeps them

forever growing and dividing, meaning that lobsters will continuously grow throughout their whole lives. And with their continuous growth, these guys can reach near monstrous sizes, with the largest lobsters ever recorded being 44 pounds or 20 kilograms, nearly 30 times bigger than the average. Wish us to put that in perspective, if humans could do this, we would end up with giant virile centenarians, possibly reaching sizes of 20 plus feet or 6 plus meters. So they don't slow down, they don't get weaker, and they certainly don't develop arthritis. In theory, they could live for a very,

very long time. But of course, it's not all sunshine and rainbows, as nature has a cruel sense of humor. You see, in order for lobsters to grow, they have to molt, which is essentially when they strip off their entire shell and then grow a new, bigger one. But the bigger they get, the harder your molting becomes, as shedding the armor alone takes an immense amount of energy, and the largest lobsters will eventually reach a point where molting is simply too taxing, causing them to literally die while trying to escape their own shell, which is painfully ironic. The shell that has kept them safe for over 100 years eventually becomes their downfall. So they've in some ways solved aging, or at least many of the negative aspects of it, but at the same time created a biological

catch-22, which ensures that they can't actually live forever. To be honest, while lobsters do not exhibit signs of aging, like mammals do, they most likely would still perish due to some age-related processes, even if we could remove the energy requirement to molting. It would just take a lot longer. But on the flip side, there are some other animals where their body itself is their greatest tool in warding off death. Case in point, Plenary and Flatworms.

These guys have gone in some ways a very similar, but in another sense, a very different direction as the lobster, having spent all their attribute points in regeneration. becoming perhaps the closest thing to a real-life Wolverine. And what I mean by this is that these derpy-looking worms can be chopped into literal pieces, halves, quarters, even slivers, and then regrow from it. And when I say regrow, I mean regrow, with each piece regenerating into a complete, perfect worm. In other words, if you cut one into three pieces, you'll soon have three different worms. And these aren't some damaged versions or a Frankenstein monster,

but rather fully functioning individuals with eyes, brains, digestive systems, everything. And I wasn't joking when I said they can regenerate from a sliver. As scientists have found that planarians can regenerate from fragments as small as 1,279th of their original size, so roughly 10,000 cells, and still rebuild themselves completely. Which, if we had this ability, it would be like growing a whole other human if you accidentally cut off your thumb, which I don't think I have to tell you is absolutely insane. And the secret lies in an abundance of specialized stem cells called neoblasts that basically act like an unlimited repair kit. These cells are pluripotent, meaning they can become literally anything the worm needs.

Muscle tissue, nerve cells, organs, anything. So if you break the planarion apart, these neoblasts won't even flinch. Instead, they'll just reorganize and then rebuild. But here's where things get really weird. And that's saying something. When you cut a worm into little pieces, each of these pieces will not only regenerate into a fully functional planary. they will also carry the memories of the original, even if the piece you cut had no brain tissue. And we know this through a very interesting but perhaps a bit sadistic experiment,

where researchers trained planarians to respond to light, and then subsequently cut off their heads, allowing them to regrow new brains. And what they observed was that these regenerated worms still remember their training, even though they again had a completely new brain. Wild. And then just as a cherry on top, a 2025 study, also found that cutting them into pieces reversed signs of aging, and not only in the new worms that were created, but also in the worm that got chopped itself, which is honestly just kind of unfair.

But if you've ever seen Deadpool, you'll know that regeneration isn't always perfect, and this applies not only to fiction, but also reality, as sometimes you get planarians who regenerate a bit odd, like with two heads and other bizarre configurations. Though unlike Deadpool's regeneration mishaps, we do actually understand whether they're going this happens in Plenarians, generally occurring when signaling proteins get disrupted during the rebuilding process. Reason being that these proteins essentially direct cellular traffic, telling new tissues what to become and which direction to face. And when the signals get scrambled, well, you end up with biological typos, basically. And though the regeneration is an incredibly

powerful ability, they, like all life forms, are still vulnerable to the basics, predation, dehydration, environmental exposure, etc. But regardless, there's no doubt that these guys are one tough cookie. But perhaps the toughest cookie of them all are Deloid Rodifers, and not necessarily because they're super hard to kill, even though they are that as well, but rather because they've somehow gathered the willpower to not have sex for an estimated 80 million years.

So they're definitely wizards by now. And why you ask? Well, because somewhere along the long road of evolution, they lost the ability to produce males, instead opting for reproduction through a process called parthenogenesis, which simply is when an embryo can develop from an egg without needing little swimmers if you get my drift. But this is not how these creatures have sized up death, as that comes from a completely different strategy. You see, these tiny creatures live in puddles, moss, and temporary water sources. And because of the somewhat unpredictability of their

tiny environments, they've developed a very peculiar behavior in response to when the going gets tough, be that droughts, freezing temperatures, or, uh, you know, even a nuclear winter. And this behavior isn't probably what you're expecting, as these guys don't simply migrate like others might do, or even hide, but rather they simply turn off, essentially. And they do this through a process called anhydrobiosis, in which they lose nearly all their water, curl up, and enter a state of suspended animation. And they can remain this way for years, surviving in a state that's barely distinguishable from death, and all that's needed to bring them back to life is a tiny drop of water. So let our boys drink.

Well, actually girls. But here's the incredible part. Being able to survive years is only in reference to regular conditions. But if they happen to get frozen, well, then they can last longer, far longer. In fact, in 2021, researchers were able to resuscitate rotifers that were found in the Siberian permafrost. And how old were they? 24,000 years old. Meaning, these were. These were. These guys were alive when we were still painting in caves and fighting off saber-toothed cats. And after they were brought to life, what did they do with their new found existence? Well, of course, they continued to reproduce like it was business as usual. And this brings me to the next absolutely mind-boggling aspect of these death-define creatures.

And that's the fact that during the drying process that lets them survive for thousands of years, their DNA will literally break apart. Now, this is crazy, not just because normally having your DNA break apart would absolutely obliterate you. I mean, this is literally how nuclear radiation kills you, but also because of the fact that herodipers are able to rebuild their genetic material when they rehydrate, and they don't just rebuild with what they have or had. But rather, they will also take DNA from whatever is available in their environment, be that bacteria, fungi, plants, essentially anything. And this is also how they avoid the downfall of asexual reproduction, allowing them to introduce new genes into their lineage.

Because remember, each child they have is asexually reproduced, and therefore, a clone. So not only are they able to survive for thousands of years in a suspended state, but they can also rebuild their broken genome using foreign genetic materials, and then use said foreign genes to spur on their species evolution. Absolutely crazy. And this amount of borrowed genes is not a small number, with about 10% of their genome being from bacteria, plants, fungi, etc. that has all been collected over millions of years.

And so while not truly immortal, they definitely seem to be on the way there. And who knows, maybe with enough gene stealing, they might hit the jackpot and really unlock the combination needed to take them to the next level. But that being said, there are animals out there that have actually reached this next level, being about as close to biologically immortal as one can get. Prime example being Teratopsis Dorney, fittingly nicknamed the immortal jellyfish. This creature basically looks like a tiny, transparent plastic bag with tentacles and is about as threatening as a wet tissue. But that's the thing. It doesn't really need to be threatening is it has a rather useful cheat code.

When life gets tough, be it through starvation, injury, sickness, or maybe if it just had a really bad day, it won't tough it out, but rather does something that is completely unheard of. Well, at least if you don't watch movies. It pulls the Benjamin button. In other words, it starts reversing its entire aging process. And it does this through a process called transdifferentiation, where an adult cells can transform into entirely different kinds, allowing the jellyfish to revert back to its polyp stage,

i.e., the infant stage, and then rebuild itself from scratch. And to be clear, it's not healing or regenerating in the conventional sense, it is literally undoing itself and starting again, pretty much like hitting Control Z on its entire existence. And it doesn't even take that long, with the transformation just taking 24 to 36 hours to reach polyp stage. Meaning, in less time than it takes to binge watch a Netflix series, this jellyfish can't completely restart its entire existence. And surprisingly, it doesn't even seem to pay a price

for doing this. Beyond, of course, losing its sense of self, memories, and having to be an infant again, as the entire process leaves no trace of damage. No mutations, no scars, just a complete biological do-over with the age counter-reset to zero. And so in theory, this could repeat forever, making it on paper truly immortal. But here's the thing. That's just on paper. This only works if the creature survives long enough to revert. And when you're a floating sea gusher, only 4.5 millimeters or 0.18 inches in size,

your odds of continuously making it through life without being eaten is slim to none. Fish, turtles, filter feeders, other jellyfish, you name it, and they're likely more than happy to cut short its infinite loop before it even gets the chance to hit the reset button once. So while it can technically live forever, in reality, it's probably not even making a year. And honestly, while this would be a super nifty ability, I don't think I love the experience of having to turn into an infant every time I want to turn back the clock or heal. So that is why, if I ever get the choice of choosing my type of immortality, I'm definitely

taking a page from this next animal, the king of immortality himself, the hydra. These guys are tiny freshwater animals that look basically like a fleshy tree, having a main trunk and tiny tentacles representing the branches, so to speak. And beyond having perhaps the coolest name on this list, these creatures have also achieved something absolutely remarkable. They simply do not age, like at all. In laboratory conditions, hydras shows zero signs of aging over their entire lifespan. No cellular damage accumulation, no tissue breakdown, no decline in biological function, and

no pain in their knees. That's a joke, by the way. What this functionally means is beyond simply not aging. They also maintain the same mortality rate throughout their entire lives, meaning a thousand-year-old Hydra is just as likely to survive another year as the newborn one. And beyond that, they also take a page from the Plenarian Flatworms book, as beyond being immune to aging, they also have absolutely incredible regenerating abilities. In fact, their ability to regenerate is so immense that hydras don't even have a slit for

their mouth. Instead, when they're ready to eat something, they will simply contract the area where it has its mouth until it will physically rip open. And after feeding, this tear will then regenerate, and they will repeat the process the next time they're feeling peckish. Now on top of this, they even reproduce through essential regeneration, wherein they will create buds that will eventually detach and then become new hydras. But of course, you can also go the brute force route, in which, if they're ever cut in half, both of these halves will regenerate to become fully fledged animals, again, like the Plenarians. And how does it do this? Well, it mainly comes

down to a family of genes called Fox O, and the fact that has a way less specialized tissue than the rest of us. And in case you're wondering, Fox O essentially acts like a maintenance crew for the body, keeping stem cells dividing and the tissue constantly refreshed. And so in short, this guy really has almost mastered death. Now at this point, you may be asking, why doesn't every creature cheat death this way? Why not evolve tricks like regeneration, suspended animation, an abundance of neoblasts and hyperactive stem cells that let you live forever?

I mean, if tiny little organisms and Deadpool can do it, why can't we? And the answer isn't that we can't, but rather that nature simply didn't select for it, so to speak. You see, evolution works in the concept of survival the fittest. But the thing is, the fittest is not necessarily the individual that can live the longest, rather just the individual who can make the most babies. And so instead of wasting energy into regeneration or long-term quasi-mortality, that energy could instead go into tools that simply make the organism really, good at getting some. And to be honest, aging itself, despite all of its brutality, has an

important function. Senesans can help wait out the weak, keep populations flexible, and limit the spread of negative mutations. But here's the thing about humans. We are absolutely terrible at accepting limitations. Show us a bird and we'll build planes. Show us a fish when we build some marines. And so naturally show us a jellyfish that can reverse aging and we'll immediately start asking, how do I give me some of that? And as it's so unsurprisingly turns out, scientists have already been asking that same question, and that actually might not be as difficult as we first thought, in a sense. Because remember Fox O that I mentioned that keeps Hydra's perpetually young? Well, we actually have the same family of genes too. In fact, it's certain genes

in this family, being hyperactive in humans, that lead to centenarians, those lucky few who make it past 100. So maybe the difference between us and Immortal Hydra isn't what genes we have, but rather how loud they speak. And we've already conducted trials in other things. animals where we caused artificial overexpression of Fox O and observed drastically increased lifespans. And the lobster's telomerase trick? Well, you've already stolen that one too. Scientists have turned off and turned on the telomeres producing genes in mice to both less

in their lifespan and is significantly extended. And there's even been attempts to deliver an overreactive telomeres gene directly into people. But of course, there's a catch. There always is. Uncontrolled telomerase is basically cancer's favorite party trick. After all, the first, quote-unquote, immortal human cells ever discovered were cancer cells that figured out how to keep telomerase pumping. So any attempt to give ourselves lobster-like regeneration has to walk a tightrope between

eternal youth and uncontrolled tumor growth. But what about the Plinarian's regeneration abilities, you say? Well, again, we actually carry many of the same genes that let these worms rebuild themselves from scraps. The difference? There are neoblast stem cells stay active forever, while ours mostly shut down after we're done growing, but scientists are now working on ways to wake our stem cells back up, essentially trying to convince our bodies that it's okay to act like a plenaryian, at least temporarily,

and they've even managed to create induced pluripotent stem cells, which is basically like taking an old, tired cell and slapping it back to its youth. So in other words, we're certainly not immortal for a lack of trying, and who knows, maybe one day we will crack the secret combo. But there is something very important to keep in mind. Every one of these animals made trade-offs we might not be willing to make, or even can make. The hydra stays simple, having a very basic body plan and limited number of cell types, the jellyfish loses its memories with each reset, and the lobster eventually suffocates in its own success, etc. But regardless, we are making some progress, and while we may never achieve the complete biological immortality of a hydra, or the total

reset of a jellyfish, the gap between doomed to age and biologically immortal is getting smaller and smaller, one stolen gene at a time. But whether that leads to humans living to 150, 200, or beyond remains to be seen. But one thing is for certain. We are definitely not going down without a fight. After all, if a blob of jelly can figure out immortality, why can't we? Thanks for watching, and until next time, on... stage on April 30th, the powerful vocals of Demi Lovato on May 17th, and the signature Southern Country Rock of Eric Church on July 19th. Tickets on sale now at yamava Theater.com, only at Yamava Resort and Casino, celebrating its 40th anniversary. You in? Must be 21 to enter.

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