Thylacine De-extinction: Why We Need to Talk About Resurrecting Species

Commentary: A research project to bring the Tasmanian tiger back from oblivion reignites debate about de-extinction.

Jackson Ryan Former Science Editor
Jackson Ryan was CNET's science editor, and a multiple award-winning one at that. Earlier, he'd been a scientist, but he realized he wasn't very happy sitting at a lab bench all day. Science writing, he realized, was the best job in the world -- it let him tell stories about space, the planet, climate change and the people working at the frontiers of human knowledge. He also owns a lot of ugly Christmas sweaters.
Jackson Ryan
5 min read
A preserved thylacine body lies curled up on a metal table. Two scientists in white lab coats handle the body.

The preserved body of a thylacine being prepared for display in an Australian museum in 2005.

The Sydney Morning Herald/Getty

When Hank Greely, a law professor at Stanford University, took to the stage at 2013's TEDx De-extinction conference in Washington, DC, he posed a simple question.

"De-extinction," he started. "Hubris? Or hope?" The answer, he offered to a smattering of laughter, was "Yes." 

Greely's talk, which you can watch on YouTube, has played on my mind a lot since US biotech startup Colossal announced on Aug. 16 that it will finance an extremely ambitious research project to resurrect the thylacine, or Tasmanian tiger. The dog-like marsupial, native to Australia, was hunted to extinction in the early 1900s. Some scientists believe that, today, we have the genetic engineering tools and bioinformatics processing power to bring it -- or something like it -- back from the dead. 

Almost a decade removed from Greely's talk, the idea of de-extinction remains controversial and hotly debated. If the thylacine resurrection announcement is anything to go by, perhaps it's even more contentious today, as climate change, pollution and the biodiversity crisis have only worsened in the past 10 years, raising questions about which problems science should be tackling. 

As for the opinion of experts and scientists, it seems like there's a 50-50 split. There are those who believe it to be a worthy pursuit, one that will lead to new conservation technologies and improve our understanding of living species so we can better protect them today.

And then there are those who believe de-extinction is simply spectacle; an unethical, misguided gimmick. Some claim the scientists involved are doing it all for "media attention" and describe the work as technically impossible. Extinction is forever, they say, and nothing can change that.

They're right. Extinction is forever. 

"De-extinction" suggests we're able to undo extinction. Reverse it. But the term is misleading. It lacks nuance. And it's even a problem in the scientific literature -- scientists don't fully agree on what de-extinction is

When the International Union for the Conservation of Nature developed guidelines for resurrecting species in 2016 it specifically noted that none of the methods to de-extinct a species will ever produce a "faithful replica." We can't undo extinction. In fact, the IUCN guideline document doesn't even use the word de-extinction in its title. It's called the "Guiding principles on creating proxies of extinct species for conservation benefit" and proposes that proxy is a much better way to define the kinds of species we will resurrect.  

Colossal's well-funded projects on the thylacine and the woolly mammoth adhere to this idea, even if their marketing suggests otherwise. The company and its collaborators will not be able to create an exact genetic replica of animals that once roamed the Earth. Nor will the team at Revive & Restore, working on resurrecting the passenger pigeon. As we currently understand things, it's impossible to bring back a species' behavioral and physiological traits (including things like its microbiome) simply by tinkering with DNA.

However, it is possible to make significant changes to the DNA, and this technology is improving exponentially. It's very likely that scientists will be able to create a "proxy" species — a thylacine-like creature, perhaps, or some elephant-mammoth hybrid — in the future. Colossal and its research team at the University of Melbourne think this can happen in about a decade for the thylacine, maybe even sooner for the mammoth. Those timelines seem overly optimistic given the technical hurdles that remain, but it's not outside the realm of possibility.

The goal of Colossal is to eventually drop its thylacine-like marsupials into Tasmania and mammoth hybrids into the Arctic tundra. This, the researchers say, will have benefits for the ecosystems and the planet. But there are so many questions to answer before we reach that point.

Which is why I keep coming back to Greely's "hubris or hope" talk. In it, he lays out both the potential risks and benefits of bringing back extinct species. He also mentions, presciently, the research won't be funded by governments or research grants. Rather, it will be bankrolled by the private sector and philanthropists. It's a future that's come to pass, so I'm inclined to think Greely knows what he's talking about.

After the news of the thylacine project broke on Tuesday, I asked Greely if there's anything he'd change from that talk almost a decade ago. He said "I think things are [largely] headed where I expected, and wanted — de-extinction as a kind of 'luxury' research project, without government funding, without hysteria, but with care."

I would argue he's mostly correct, though there seems to be a little extra hysteria creeping into the narrative these days. The most common argument against de-extinction I've seen since Colossal's announcement is that scientists are wasting money and time trying to bring back extinct species when we're living through a biodiversity crisis and sending creatures extinct at an unprecedented rate. This is, presumably, heightened by the fact we continue to see climate change wreak havoc on all life on the planet.

Another common argument is that if we have the technology to "de-extinct" species, then extinction doesn't matter anymore. This is a curly moral hazard but it's definitely not the case de-extinction should render extinction irrelevant. Even if it did, should we stop researching the methods needed to bring species back? Should we stop funding these projects altogether? Would that be prudent?

I liken it to the solar geoengineering experiments that would potentially dim the sun with aerosols. Scientists aren't really keen on having to deploy these measures, but what if it became so bad that we had to? Should we not, at the very least, conduct the basic research and science experiments to know? One of the most famous solar geoengineering experiments, Scopex, faced public backlash for not adequately engaging with the community about the experiment it was set to run. As a result, it began a "robust and inclusive" round of engagement with the public. 

The conversation needs to begin for de-extinction, too. 

What any de-extinction project should do, before we ever get to holding a baby thylacine in our arms, is discuss exactly how such a project will work with all the key stakeholders, from the public to other scientists and industry, as well as with government.

Because if de-extinction researchers truly believe they can resurrect something that walks, runs and weirdly opens its jaw like a thylacine — and they seem to believe they can — then we need to understand where and how these creatures might be returned to the world. We have to know if the public would even want that. Projects like those overseen by Colossal need to start discussions with traditional owners of the land where they might repopulate with a pack of thylacines or elephant-mammoth hybrids. They need to better understand how the creatures might experience pain or suffering once they're brought into today's world, a world that is drastically different from the one their ancestors departed. They need to consider the environmental impacts and the ecosystems they are attempting to alter and convey the risks and uncertainty in the process.

And we need to weigh up, as Greely did, the risks and the benefits. Each of us. For the final word, I'll turn to the professor once again.

Ending his TEDx talk in 2013, he said, "I'm just one voice. I'm not gonna make this decision — you're gonna make this decision."

Updated Aug 21: Edits for clarity around bringing back species as they once were.