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Frequently Asked Questions

FAQs Answered by Stewart Brand

Why do it? Why revive extinct species?

For the same reasons we protect endangered species. To preserve biodiversity and genetic diversity. To restore diminished ecosystems. To undo harm that humans have caused in the past.  To advance the science of preventing extinctions.

Won’t reviving extinct species make people stop caring about protecting endangered species?

It is likely to make them care more. The costs and difficulty (maybe impossibility) are vastly greater for reversing extinction than for heading it off. Preventing extinction is hard enough; reversing extinction will be highly expensive and maddeningly slow. In most cases, once a species is gone, it will stay gone. First protect the living.

How soon will some extinct creature live again?

Signs are there will be some impressive milestones in this decade. Technically one extinction has already been partially reversed. The last Pyrenean ibex (also called a bucardo) died in 2000. A Spanish team used frozen tissue to clone a living twin in 2003, birthed by a goat. The baby ibex died of respiratory failure after ten minutes (a common problem in early cloning efforts). Funding dried up, so no further work has been done on this species as yet. As George Church reminds people, the first airplane flight in 1903 lasted 12 seconds.

How many de-extinction techniques are there, and how do they work?

There are at least three semi-successful techniques for de-extinction so far.  1) Selective back-breeding of existing descendents to recreate a primordial ancestor is being used for the revival of the European aurochs, among others.  2) Cloning with cells from cryopreserved tissue of a recently extinct animal can generate viable eggs.  If the eggs are implanted in a closely related surrogate mother, some pregnancies produce living offspring of the extinct species.
3) Allele replacement for precisely hybridizing a living species into an extinct species is the new genome-editing technique developed by George Church.  If the technique proves successful (such as with the passenger pigeon), it might be applied to the many other extinct species that have left their ancient DNA in museum specimens and fossils up to 500,000 years old.

If you bring the genome of a species back to life, are you really bringing the species back to life?

That remains to be seen. It is one reason to do the research: is the genome the species? The answer will vary from species to species. But if California condors had gone extinct, it’s unclear if they could have been brought back fully, because the young rely on parental training. Passenger pigeons got no significant parental training, but can new ones function without a flock? Can young mammoths be reared successfully by a herd of their close relatives, Asian elephants? Once something is returned to the wild, how much does the wild teach it?

Even with exponential advances in bio-technology, de-extinction projects will not produce species that are 100% genetically identical to the extinct species, due to the constraints of working with incomplete ancient DNA.  It is expected that the revived species will be nearly identical genetically, and “functionally identical” ecologically.  They should be able to take up their old ecological role in their old habitat.  Revived woolly mammoths, for example, should be able to convert parts of the northern boreal forest and tundra into “mammoth steppe” grasslands, as they once did.

How long will it take to bring extinct species all the way back?

De-extinction is not a “quick fix” science.  Most species revival projects will take many decades.  First, extensive research about a candidate species is conducted before moving into a lab setting for genomic work to revive the species.  Then, once the initial revival is completed, the species will be bred in captivity, preferably with genetic variability introduced from the genomes of a range of specimens or fossils.  The growing population will be studied and then eventually moved to quarantine areas for further observation and analysis.  Getting the okay from regulatory agencies will be required before the animals are ultimately re-introduced to the wild.

Passenger pigeons, for example, will initially be bred in captivity by zoos, then placed into netted woods, and then finally re-introduced to portions of   their original habitat—America’s eastern deciduous forest.  Before that happens,  The US Fish and Wildlife Service and regulatory agencies in the relevant states will have to agree to welcome the resurgent birds.

It all sounds like “Jurassic Park.” How is this different?

It was a wonderful movie, which introduced the world to the idea of de-extinction back in 1993.  Its science fiction is quite different from current reality, though.  First, no dinosuars—sorry!  No recoverable DNA has been found in dinosaur fossils (nor in amber-encased mosquitoes).  Robert Lanza observes, “You can’t clone from stone.”

Second, the plot of the movie is driven by protecting the commercial secrecy of an island theme park.  Real-world de-extinction is being conducted with total transparency.  Eventual rewilding of revived species can be no more commercial than the current worldwide protection of endangered species and wildlands. Ecotourism, of course, is a commercial activity often used to help fund the management of protected areas.

Revive & Restore is a nonprofit 501(c)(3) public charity.

Journalist Carl Zimmer answers questions from readers of his blog, “The Loom”

Carl Zimmer
National Geographic
Phenomena: The Loom
Published March 19, 2013 

I was down in Washington to speak at (and mostly watch) TEDxExtinction, a day-long meeting dedicated to exploring the possibility (and advisability) of bringing extinct species back into existence. The meeting coincided with the publication of my story in National Geographic on the subject. I invited readers to ask questions raised by either the story or the meeting, and then National Geographic hosted a tweet chat, which became an hour-long rapid-fire volley on Twitter. Here are some answers to a few of the questions from that event, first on the logistics of de-extinction, and then the ethics.

How long is it ok to be extinct? Dinosaur and Dodo de-extinction are different issues, right?

This is an interesting question, because dodos were dinosaurs. Not to mention robins and hawks and other living birds. If your idea of Jurassic Park is being surrounded by dinosaurs, you are living the dream. If, on the other hand, you desire (or fear) the lineages of dinosaurs that became extinct 65 million years ago, such as tyrannosaurs, then you are out of luck. No viable cells or nuclei can survive 65 million years. And while scientists have recovered lots of DNA from species that became extinct tens of thousands of years ago, they can’t reach back tens of millions of years.

Too bad the dodo died out too long ago for viable DNA to survive. Now THAT I’d love to see.

Dodos only became extinct less than 400 years ago. While there are no intact dodo cells left today, scientists have retrieved bits of dodo DNA from a specimen stored at the University of Oxford. If scientists could find a lot more dodo DNA, they might be able to identify the genetic variations that turned the ancestors of dodos–small, flying pigeons–into big flightless birds. Then they might be able to reverse engineer the genome of a stem cell from a closely related pigeon species and then turn that cell into eggs and sperm, which could produce dodos.

And, could we avoid genetic drift-driven extinction for a small population of de-extincted animals?

When a population gets tiny, its genetic variation gets tiny, too. Thanks to the random shuffle of heredity’s dice, gene variants can disappear, leaving organisms more and more similar to each other. That can be dangerous because it can leave populations unable to reproduce as quickly and may leave them less capable of adapting to new challenges.

If scientists created a dozen genetically identical dodos from a single egg, they’d face some serious problems with genetic diversity. This is just one of many practical challenges scientists would face in trying to truly revive a species, rather than getting one animal alive again just long enough to be photographed. But we should not assume these challenges are insurmountable. It might be possible to find variants of genes in ancient DNA from fossils or museum specimens, for example.

If 99% of all living things are extinct, why are we so consumed with "playing God"? Things come, thing go, that’s it.

I agree that it is important to think about Deep Time when we think about extinction. Perhaps 99.99% of all species that ever existed are gone from this planet. But what’s happening now is unusual for two reasons.

One is the rate at which species are going extinct. In the past few centuries, the rate of extinction for some groups of species has jumped by roughly a factor of a thousand. That jump is due to us–to our hunting, logging, and other actions that leave species struggling to hold on to existence. If those actions continue into the future, and if we continue pumping carbon dioxide into the atmosphere at a rising rate, we could jack that extinction rate to levels that life has achieved only five times in the past half billion years.

So we’re not in a “things come, things go” situation. It’s more like, “Things go, and a lot more things go after them.”

The other reason that what’s happening now is unusual is us. In no previous pulse of mass extinction did a single species consciously drive a number of other species extinct. I’m not saying that a bird hunter shooting into a flock of passenger pigeons 200 years ago realized he was part of an exercise that would drive the entire species of passenger pigeons extinct within 100 years. But as a people, we know it now. And we know that other species are on the ropes, because of what we are doing. Hence we can decide if we want to let this extinction crisis continue to balloon.

The whole conservation movement is organized around the proposition that biodiversity is something worth saving. When a species goes extinct, it can leave a hole. Its ecosystem may suffer because the species can no longer carry out some important task, such as pollinating plants or filtering water. We lose the opportunity to investigate its biology and discover some fascinating piece of natural history or even find a valuable molecule for curing infections or sequencing DNA. And we end up living in a world without Great Auks and gastric brooding frogs.

Is de-extinction a tool for slowing or reversing this trend? Possibly. But one thing is for sure. We’re not playing God. We’re coming to terms with our own powers, as well as the unexpected results of our actions.

Should we bring any animal back from extinction which could threaten human life?

What constitutes a threat? We have a habit of perceiving threats where the risks are tiny or non-existent. In fact, some species, such as the thylacine, were eradicated because they were considered a threat to human life–specifically, that they were killing off herds of sheep. That was untrue, but it didn’t stop people from driving the species extinct. Bringing them back would not pose a threat either.

I’m not saying that no revived species would pose a risk. But we do have to make sure we aren’t letting emotions ride roughshod over our decisions. Scientists have already revived a very dangerous life form: the flu virus that killed 50 million people in 1918. But no one has died from it, because precautions have been taken. And scientists have learned a great deal about how influenza evolves and kills–information that could help us in the future. This was a de-extinction of sorts that presented both risks and benefits.

Wouldn’t resources be better spent preventing extinction before de-extinction were necessary?

This is a point raised by many conservation biologists, both in my interviews for my article and at TEDx. “At this moment, brave conservationists are risking their lives to protect forest elephants from armed poachers,” David Ehrenfeld of Rutgers University said at the meeting. “And we’re talking in this safe auditorium about bringing back the woolly mammoth?”

If de-extinction really did make it harder to, say, pay guards to stop poaching, then I could definitely see a problem here. But where is the evidence of a zero-sum game at play? I don’t see it. No one at TEDx proposed cutting guard salaries to bring back a mammoth.

This concern could apply just as well to experimental research on animal reproduction–efforts to freeze cells of endangered species for research, assisted reproduction, and so on. They all cost money, they are not guaranteed success, and they all require people to do something other than guard against poaching. Yet some species have been introduced back to the wild, saved for now from extinction, thanks in large part to this kind of research.

These issues don’t just apply to extinct animals, but to the near-extinct. There are four Red River giant softshell turtles left on Earth. They are not breeding with each other. We might be able to use stem cells to produce lots of new sperm and eggs and fertilize them to grow their population. Is this just a waste of resources, or will this end up saving the species? If we engineer frogs to resist chytrid fungus infections, is this just a simplistic technological fix, or the only way to keep them from going extinct?

My fellow Phenom blogger Brian Switek considers de-extinction little more than a slick marketing term. I disagree, if only because the issues that have emerged with its unveiling are going to stick around for a long time, even if no one tries to bring an extinct species back to life.

Do you think it would be ethical to reverse the extinction of Neanderthals?

If you want to go deep into everything that would be required in bringing back Neanderthals, check out this piece by Virginia Hughes. Do not worry about meeting a Neanderthal on the street tomorrow, or next year.

If we could bring them back, should we? I think not, for many reasons. Neanderthals were humans, and research on humans requires informed consent, which is hard to get from someone who belongs to an extinct lineage. It would be unethical to bring people back without a place where they could live with dignity, and we have no idea what such a place would be for a Neanderthal in the twenty-first century.

Ethics and feasibility aside, if you *could* resurrect a species, which one would you go for?

I am quite taken with the idea of bringing back Steller’s sea cow. The first scientist to describe it was Georg Wilhelm Steller, who was on a voyage across the Bering Sea in 1741. He and his crewmates were shipwrecked on an island there, where they discovered herds of these amazing animals. They were relatives of manatees, reaching 25 feet long or more and weighing six tons. Here’s a wonderful image of them by the great illustrator Carl Buell, which is now on display at the Smithsonian.

Steller survived to write about the sea cows because his crew slaughtered some of the animals to eat on the voyage home. A single sea cow could feed a crew of 33 sailors for a month. Sailors on North Pacific ships killed so many sea cows that they vanished in 1768, just 27 years after Steller first described them.

Steller’s sea cow was part of the Pacific ecosystem for millions of years, and we are personally responsible for wiping it out. It would be quite something to figure out how put it back where it was just a couple centuries ago. But given the size of their potential surrogate mothers–not to mention many other obstacles–I’ll content myself with a daydream for now.