Extinct Animals Science Wants To Bring Back

It's too bad modern humans will never get to see a real woolly mammoth ... or, will they? That's the plan behind a company called Colossal, which received $15 million in private funds to continue working on bringing the woolly mammoth back to life. According to The New York Times, the company's head, Harvard Medical School biologist George Church, had been working on the project on a small scale for nearly a decade when they were awarded the massive amount of funding.

The idea is that they're going to be taking elephant DNA, and mucking about with individual genes to add, subtract, and tweak elements that will give these new creatures the traits of the woolly mammoth — like their heavy fur coats, fat stores, and ability to thrive in extreme cold.

There's actually reasoning behind this, aside from "Look what we can do!" CNN spoke with Love Dalen, a professor of evolutionary genetics at the Centre for Palaeogenetics in Stockholm. Dalen says the work has merit — particularly in re-establishing genetic diversity in endangered species — but there's a catch. The genetically engineered creatures aren't technically mammoths but are, instead, "hairy elephants," so the hopes of releasing them into the Arctic and rebalancing the ecosystem is ... iffy. There's a theory their reintroduction might help stabilize the area's permafrost, but the evidence is lacking. There are also the ethical concerns of putting the lives of elephants at risk to make them act as incubators for the baby almost-mammoths, and bottom line? It's complicated.

New Zealand Birds Online describes the moa as a group of giant, flightless birds that — once plentiful — were driven to extinction thanks to overhunting from humans. The little bush moa (skeleton pictured) was one of nine different species, and it made headlines in 2018. That's when researchers from Harvard University completed the first step in "de-extinction": the completion of a full genome, using DNA taken from the toe bone of a little bush moa that had his (or her) final resting place in a not-so-peaceful museum.

It was no small feat, according to Stat News. DNA starts decaying from the time of death, and it was described sort of like taking a shattered glass and trying to piece it back together — only in this case, the research team was dealing with 900 million nucleotides (the base building blocks of DNA), and millions of DNA fragments — which then needed to be pieced together to build the genome.

Skeptics, however, have cautioned about the practicality of this for a number of reasons (via the New Zealand Herald). Not only would there have to be a large number of individuals created and cloned to allow a wild population to support itself without inbreeding and collapse, but the environment has changed in the 600 years since extinction. The result could be an animal "inherently maladapted" to the modern world. Meanwhile, others — like IdeaLog — suggest the funds would be better spent protecting the endangered animals that are still around, like the kiwi.

There have been plenty of cautionary tales told about the dangers of messing with dinosaur DNA, but that hasn't stopped real-life scientists from giving it a go. And the results? They've been ... interesting and disturbing at the same time. In 2016, researchers from the University of Chile decided to muck about with the DNA of perfectly ordinary, perfectly innocent chickens. According to Science Alert, they didn't need dinosaur DNA to reverse-engineer modern chickens into something more like their ancient ancestors, and by basically turning off a gene called IHH, it prevented the gene from halting the growth of the fibula. With that gene turned off, chickens grew bones that looked disturbingly like the bones of the ancient Archaeopteryx.

The Smithsonian said that something similar had been done a year prior, when paleontologists at the University of Chicago led a study to tweak chicken DNA to give embryos snouts instead of the standard beak. They were just trying to find out how beaks evolved in the first place, but with further advances, they just might have the tools to go one step further.

In 2020, National Geographic reported on findings that came out of the Institute of Vertebrate Paleontology and Paleoanthropology in China. Researchers had found what looked like dino DNA in the remains of a 75-million-year-old skull, and more dino DNA — this time from 120-million-year-old fossils — was (possibly) found in 2021. While researchers say (via LiveScience) that they're far away from rebuilding an entire dinosaur, this could be the first step.

The thylacine — or Tasmanian Tiger — is definitely extinct, says The New York Times. Still, that hasn't stopped the buzz about it, and in recent years, there have been more reported sightings of the Thylacine than of Bigfoot and Elvis combined. That's given rise to a fascinating conversation about perception and interpretation of things like photographic "evidence," but just as interesting is the fact that someday, people might be seeing actual, living thylacines again.

This weird sort of marsupial dog only went extinct fairly recently: According to National Geographic, the extinct designation was only made official in 1982, the last captive animal died in 1936, and it's believed the last wild ones died in the 1940s. Examining DNA from a 108-year old baby thylacine was meant to be an experiment that would hopefully determine how wolf-like they were, and in 2008, that escalated into taking that DNA, injecting it into a mouse, and seeing it actually function to guide bone and cartilage development.

Then, it escalated quickly. In 2010, the preserved remains of a thylacine joey yielded enough DNA that researchers from the University of Melbourne called it (via Cosmos) "the roadmap for getting a thylacine back." The idea has then become to rebuild the thylacine genome, gestate it in a surrogate or an artificial womb, and see what pops out. Project leader Andrew Pask says that while there's some big hurdles in the way, "you never know how fast some of these technologies will develop."

According to Trent University's Eric Guiry (via The Conversation), passenger pigeons went from numbering in the billions — flying in flocks so large that they were once called a "biological storm" — to gone in just around 40 years. The last died in 1914, and it was the end of a species that was found to have been completely decimated by wanton, large-scale slaughter.

Now, however, an organization called Revive & Restore is working on bringing them back. The idea is to take a flock of rock pigeons that have been engineered to include something called a Cas9 gene. Without getting too sciency, that's the gene that allows for the use of a gene editing tool called Crispr, which scientists plan on using to add DNA from the extinct passenger pigeons to new generations of rock pigeons.

In 2019, the program saw the birth of its first pigeon that contained the Cas9 gene. His name was Apsu, and while they also found that it was highly unlikely he would pass the gene on to his offspring, it was a start — and they were still hoping for the first new passenger pigeons to hatch in 2025. Not everyone is thrilled, though, with some ornithologists — like David E. Blockstein of the National Council for Science and the Environment — claiming that it's not just unethical to de-extinct the pigeons, but it could be devastating to an environment that's no longer used to having them around.

The ancient steppe bison was a pretty big deal: According to the Yukon Beringia Interpretive Centre, these were not only one of the few megafauna to survive through the last Ice Age, but when they spread from their native lands in Asia, they crossed the land bridge into North America and gave rise to America's famous bison. They went extinct sometime during the Holocene period, but according to the International Business Times, they might once again be thundering across the steppe ... if science has anything to do with it, that is.

In 2016, an ancient but well-preserved steppe bison tail was discovered in the permafrost around the Indigirka river basin. Researchers from the North-Eastern Federal University date the tail to around 8,000 years ago and are pretty sure it's intact enough that it'll yield some DNA.

That DNA, they say, would then be used to create clone embryos of the steppe bison, which could — in theory — be implanted into a cow. They estimate the baby born to the surrogate mother would be "99.8% newborn bison," but that's a bit down the road. Before trying it with a steppe bison, scientists said they first needed to learn how the process worked and if it was even viable. That meant testing it first, and the successful cloning of a Canadian wood bison would have to be done before attempts were made at bringing back the steppe bison.

Tarpans were once the wild horses of Middle Europe and Asia: Hardy and strong, their story ends with, of course, extinction. But here's the thing — according to the World Wildlife Fund, some of the last remaining tarpans weren't killed, they were caught and cross-bred with the domesticated workhorses of early 19th century Poland. (Rewilding Europe notes, however, that the last known wild mare was killed during attempts to catch her.) That created an entirely different breed that was the best of both worlds, and it was called the Konik Polski.

Not that many generations had passed when, in 1936, breeders started choosing Konik horses that had traits more like the ancient tarpans than their workhorse ancestors. By 2005, there were 2,500 almost-tarpans living in a reserve in Latvia.

There's a huge "but" here, and that's the fact that they're not really true tarpans. According to the True Nature Foundation, there are actually other horse breeds — like the Exmoor pony, the Fjord horse, and a handful of breeds from Spain that are genetically closer to Europe's original wild horses than what the Konik is. Should those looking to bring back the tarpan look elsewhere?

The Xerces blue butterfly is an example of a creature that's small yet mighty — even though it truly didn't become powerful until it vanished. According to WTTW PBS, the butterfly was the first species that scientists were able to prove went extinct solely due to human interference. In this case, it was habitat loss: As populations grew out from the San Francisco area, the landscape was changed, field and sand dunes were turned to pavement, and native flowers disappeared.

The Xerces blue butterfly became a symbol of the damage humankind has done, and in 2021, Science News says that conservationists got the news they were looking for. DNA extracted from a 93-year-old specimen from Chicago's Field Museum proved that not only were people to blame but that the butterfly was, in fact, a separate species and not a subgroup as some had argued.

The butterfly's status as an icon for conservation has also gotten it attention as a candidate for de-extinction, thanks to recent developments in the field. In addition to mucking about with DNA, there's another theory, too: Some scientists believe that thanks to a habitat restoration project, introducing a closely-related butterfly might kick-start a re-evolution of the Xerces. Still, Felix Grewe, Xerces researcher and co-director of the Grainger Bioinformatics Center, summed up everything that needed to go before de-extinction: "Before we start putting a lot of effort into resurrection, let's put that effort into protecting what there and learn from our past mistakes."

The Southern gastric-brooding frog went extinct sometime in the mid-1980s, and scientists want to bring it back, if for nothing else than pure amusement. See, the gastric-brooding frog didn't pick its name out of a hat — it was called that because it literally gave birth from the mouth. Eggs would be laid into the mouth, and travel into the stomach. The stomach would then turn into a uterus, where the eggs would incubate. When they hatched into tadpoles, they would remain in the stomach/uterus until they matured into tiny frogs, at which point they would birth themselves from mama's mouth. These were the only organisms ever known to reproduce this way, and ... we wanna see it.

In 2013, researchers funded by the Lazarus Project succeeded in growing embryos containing the revived DNA from the gastric-brooding frog. They accomplished this by inserting the dead material from the extinct frog, into donor eggs from a living species. The eggs continued to grow into embryos, the first time such a technique was achieved for an extinct species. Continued analysis proved that the cells from the extinct frog were multiplying, which allows for the potential for us to one day gawk at a frog that literally hiccups babies from its mouth.