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The year is 1861, November. 20 years ago, John Edward Gray recorded a skull of a new form of killer whale. The skull itself is 126,000 years old, and the species declared extinct. Case closed. Or so we thought.
3 months ago, a new species of orca, no pseudo orca, washes ashore in the Danish town of Cullenborg. Its skull, an exact match of the extinct orca. This false killer whale has risen from the grave as Lazarus himself, and it will surely not be the last. The question becomes, how do we know when a species is truly extinct? And what more rues does mother nature have in store for us? It would seem we have a mystery of natural history on our hands. And it is one that I am sure to get to the bottom [Music] of.
An animal is extinct when there are no living members of the species anymore. We know this. The opposite of this is extant, meaning they are still around. A lot of cases of extent versus extinct are obvious, but some cases become very blurry, and some are so blurry the rules might not even work properly. Let's start with what we know. This is a Tyrannosaurus Rex. It is a dinosaur. It is extinct. We know that. This is a sparrow. It is a dinosaur. It is not extinct. Wait, what? But dinosaurs are extinct. Yes. And also, no. You see, birds are dinosaurs. They evolved from an ancestral species of dinosaur. And after a meteorite hit the Earth 66 million years ago, birds survived and the other dinosaurs did not. You may have heard a term in some other documentaries or YouTube videos, cough cough. like mine cough cough that use the exact phrase the extinction of the non-avian dinosaurs. That's the phrase we now use since discovering that birds or avens are dinosaurs. This means that together we have now concluded that birds are still alive and non-avian dinosaurs are extinct. We've drawn that line in the sand and it's mostly clear. But now we've found the case of one specific dinosaur. It is significantly less clear.
This bird is from Australia. It looks very similar to the kakapore of my home Alterero in New Zealand, but it isn't very related. And unlike the cockapore, this bird can fly. It just chooses not to. Its name is the night parrot or midnight cockatu. And it's part of a genus that includes ground parrots. It's unusual to see parrots that don't feel like flying, but this bird makes it home in the very dry and very dusty outback of Australia where most of the plant life is spin effects grass. In 1912, there was an authenticated report of a sighting of this parrot, but then it disappeared without a trace and it would not be spotted again for some time. Considering that this bird lives in one of the more hostile regions of the world for humans in thick brush that it rarely leaves, it's not the biggest shock that we couldn't find them.
But a few decades later, across the other side of the planet, something important was happening in the world of global conservation. I'm not sure if you are aware of this, but in the late 1930s through to the 1940s, there was a war. They called it the Second World War. As a result of this, an intergovernmental organization was created called the United Nations that aimed to achieve international cooperation. And it was formally agreed that part of this international cooperation included revitalizing a means of global scientific and cultural cooperation. The proposed solution was to form an arm of the UN named the United Nations Educational Scientific and Cultural Organization or UNESCO, which you may know from their creation of heritage site statuses around the world. The year is now 1948 in the city of Fontaine Blur, France. Global representatives of both governments and conservation organizations have gathered having been spurred into action by UNESCO to create an international group that is dedicated solely to protecting nature. Documents were signed. A group was formed and the organization we would come to know as the IUCN or International Union for the Conservation of Nature was born.
That is a lot of organizations to run through, all focused on cooperating across borders and cultures. But the IUCN has produced, among other things, the global red list of threatened species. Historically, this is generally considered the go-to source on the conservation status and risk of extinction for species around the globe. And it is where we get the phrase endangered species from. Starting in 1966, this red list categorized how at risk of extinction animals were with a tier system that is judged based on a variety of factors relative to the animal itself, including initial population size and rate of decline, right through to how fragmented the habitats of the species have become. These tiers included the term that everyone now knows, endangered species, which is defined as very high risk of extinction in the wild. Worse than that, you get critically endangered, which means on the brink of extinction as a species. Then we have the pieces we are looking at today. Extinct in the wild means that there are no longer any living individuals in their native habitat. These animals still exist in captivity though, such as zoos or are kept domestically for cultivation, so they are still around, but not where they naturally from. The final tier is extinct. Quote, "By reasonable doubt, this species is no longer extent."
So, what does beyond reasonable doubt look like? We looked at the Tyrannosaurus Rex earlier, and we know that is extinct because its fossils stop appearing 66 million years ago with most other dinosaurs, and it would be a little obvious if there were still 5-tonon dinosaur predators wandering North America. But it becomes so much harder to tell when an animal like the midnight cockatu disappears when we have a recorded sighting as recently as 1912. They could by all means still exist in the spin effect shrublands of the Australian outback. To figure out if the midnight cockatu is truly gone, scientists must show that exhaustive surveys have been conducted in its known and likely habitats. And the surveys must be over an appropriate time frame based on the species life cycle and ecology. Some groups suggest waiting at least 50 years of no sightings before declaring an animal extinct, but this is not a hard and fast rule. It's more of an easy and slow suggestion.
This parrot was considered by many to be extinct. While some continued the search to find if more existed, Shane Parker, an ornithologist from the South Australian Museum, claims to have spotted a flock in 1979, but was unable to capture evidence. Then in 1990 in Queensland, scientists found a midnight cockatu that had unfortunately been hit by a car. Clearly, the species wasn't actually extinct, as many had thought. In 2005, as part of a survey to assess the environmental impact for the development of a new outback iron mine, three of these parrots were spotted without photographic evidence, but the detailed descriptions from the witnesses was accepted as confirmed sightings by scientific peers. A few more sightings and unfortunately no longer alive specimens were found over the course of a decade before a living midnight cockatu was successfully captured and tagged for conservation. Now this species is officially listed on the IUCN red list not as extinct but as critically endangered. Feral cats are one reason that has been identified as a reason why these already reclusive birds are not doing great populationwise. But in 2024, a stronghold breeding ground of around 50 individuals was found in Western Australia. How have they survived? One theory is that this area is dingo capital, and that's not a great place to be if you're a feral cat.
This story of finding species that were thought to be extinct is not unique to the midnight cockatu. The takahay of my home was considered extinct for exactly 50 years, reaching a population as low as 118 individuals in 1982. But since the rediscovery and conservation efforts, the population is now around 500 individuals for this nationally recognized species. The very rare South American masupial monito deloan peckery, the false killer whale, and very recently the atenbur's akidna of papu guinea are just some of the several species considered extinct at one point but are actually still alive. We call these species Lazarus taxin after the bible story of Lazarus who was resurrected after being deceased for 4 days. These Lazarus taxin are astonishing stories of survival, but perhaps none more astonishing than the curious case of the celacanth.
The celacanth is a fish, a very old fish. Celacants evolved during the Deonian period about 410 million years ago, evolving alongside the first sharks, well before the first dinosaurs, even before the first reptiles. They had a great stint and then they went extinct about 66 million years ago during once again the meteorite impact that wiped out the non-avian dinosaurs. This makes them one of the longest running animal lineages in history. December 1938. Marjgerie Courtney Latimer receives a call from some local fisherman in her role as curator of the East London Museum. And this call wait no no sorry. East London isn't in England. Well, it is, but this one is in South Africa. Thanks. This call mentioned that the fishermen had pulled up some quote garbage fish, but previously she had mentioned to them that if they did find anything unusual in their nets, they should call her. And so, she went down to investigate. Imagine the surprise when sitting on the pier in front of her was a fresh fish that went extinct 66 million years ago. This discovery shook the world of zoology. This species was not just a Lazarus taxin. This was some kind of phantom or ghost.
Ghosts lineage is a real term. These are animals that have a big gap in their fossil record. The assumption is that the animals continue evolving as normal in between the fossils, but we don't know exactly what happened or where because we don't have fossils from this time. Typically, ghost lineages occur when comparing fossils to other fossils where we have a space of tens or even hundreds of millions of years with no fossil evidence of this group of animals. The same concept can be applied to the steelanth, this fish that disappeared for 66 million years and could be retroactively extended to the false killer whale where we initially found that 126,000-year-old skull before finding out they were still alive.
This isn't the only animal we've discovered in fossils. First, several of the Lazarus taxin we already looked at were first discovered as fossils. Chinchilla rats, named after chinchillaas, not actually chinchillaas, were first introduced to Western science after their remains were found in an Incan tomb in South America. While technically not fossils, we found them as bones first. A different species of chinchilla rat was discovered alive in 1999 before that same first fossil species we found were photographed at no joke Machu Picchu itself. Going back even further than the celacanth, there is a species of fly originally discovered Jurassic Park style encased in amber 100 million years ago before being found in Namibia in 2010. And at the most extreme end, monoplacora is a class of mollisks that was thought to have gone extinct 375 million years ago in the Deonian period. They live in deep waters off the coast of Costa Rica today. The evidence suggests that these animals are all the same species, genus, or class as the extinct animals that we are missing fossil records of. And it is astonishing that we have found any of them still alive.
But there is another possibility that we need to consider. This is the possibility of convergent evolution. And it takes us to the case of the Aldabra rail. For those that have been following me for some time, you may know that my first video was on convergent evolution. And if you'd like to know more about how it all works, I'll leave a link to that below. Simply put, convergent evolution is the process in which two or more unrelated species evolve the same or very similar traits to one another. This often leads to animals that aren't related having similar body plans, but it can also lead to an animal kind of seeming like they have re-evolved.
Alabra is the second largest atole in the world. It sits off the coast of Africa and Madagascar and harbors some incredibly unique wildlife. And this atole is home to the interesting convergent case of the Aldabra rail. This rail is not a species but rather a subspecies of the whitethroated rail predominantly from Madagascar. Except the Aldabra rail has evolved to make itself at home on the Aldabra atal becoming completely flightless. There is one problem with adapting to being flightless on a low-lying island in the middle of the Indian Ocean. It's a very easy location to flood. Nearly 140,000 years ago, this atole experienced exactly that. The island flooded, lasting around 20,000 years, creating a complete turnover in the species that lived there and wiping out a different subspecies of flightless white-throatated rail. The flooding ended. The atal resurfaced and soon the whitethroated rail from Madagascar found it again. Then these individuals enjoyed the atal so much that they once again evolved to be flightless. And now we have the aldabra rail. This rail is not the same animal as the original extinct subspecies from the atal, but it is very very nearly the same animal. Both were flightless and evolved the same body plans to live life on the atal. This has led to a lot of headlines claiming that this species has quote re-evolved itself back from extinction. The Aldabra rail is now the most commonly touted story of a phenomenon with the most ridiculous name, Elvis Taxin, because the new animal is an impersonator of the original. We have very few examples where we know for sure that this animal is an Elvis Taxan. But these animals haven't brought themselves back from extinction and they aren't Lazarus Taxan because they are a separate animal that has found the same solutions to the same problems as animals that have disappeared. They just look the same.
Only one animal in the world has the title of actually coming back from extinction. It's the morally questionable and unfortunately sad case of the Pyreneean ibix. The Iberian ibex is a mountain goat from the Iberian Peninsula and it contains four subspecies, two of which are extinct, predominantly caused by humans. One of these subspecies was going extinct in the late '90s, and I mean 1990s. This was the Pyrenean ibex. The last of these ibex was named Celia, and she had been living her life alone in a Spanish national park. Further north in Scotland, a vaguely genetically similar animal had made global news. Dolly the sheep had become the first successfully cloned animal in history. This news reached an American biotechnical company who approached the Spanish government. Celia was the last of her kind. But what if she wasn't? Scientists took a sample of Celia's genome and cryogenically preserved them. They intended to use this DNA to follow the exact same procedure as Dolly sheep through nuclear transfer to start cloning the Perinan ibex. This would allow them to use a different subspecies of Iberian ibex as the surrogate mother that would carry the baby clone to term. But the surrogate mother would not give a clone any of their own DNA. This way, the clone would genetically be a Pyrenean ibex.
In the year 2000, a year after the sample was taken, Celia, the last of her kind, was unfortunately lost to a falling tree. The Pyneean ibex was now extinct. After this extinction, the Spanish government agreed to allow the American company to attempt to clone Celia and take the first step in bringing the ibex back. 3 years later, after nearly 60 attempts, the scientists succeeded. The cloned ibex was born with a growth on its lung and survived for only 10 minutes. For 10 minutes, the Pyrenean ibex was no longer extinct. The story of this ibex is, in my opinion, pretty awful. Personally, I am torn about the ethics of cloning an animal like this, even an animal that's going extinct. But I'll leave the philosophical debate to you and maybe another video in future. This ibex is now the only animal to have ever truly come back from extinction and the only animal to go extinct twice.
Extinction, as we've seen, is not something we are always sure about. Sometimes animals that we thought were extinct for millennia wash up on our shores. Some extinct animals could still be out there, although most animals are definitely gone. One thing we do know is that even with the power to clone species, extinction is pretty final. And our role in causing so many of these extinctions, which are happening every day, means that our role should also be able to prevent them in future. We may think that these animals are extinct, but sometimes it's worth it to keep looking because maybe we'll find the last few of a species that we thought was gone, and together we can bring them a little further away from the brink. Thanks so much for watching. I'm Ben, the quasiologist. This is the natural world explored, and until next time, stay curious, friends. Hey, I hope you enjoyed this natural history mystery. I love making these and if you love watching them, I would greatly appreciate the old like, the old subscribes, the things that people always say in videos so I can reach more people and we can all explore together. See you in the next one. Tonic.