Bring Back the Woolly Mammoth? UVA Law Professor Weighs Ethical, Legal Implications of Cloning Long-Lost Species

Collectors are digging up woolly mammoth tusks as a "legal" alternative to elephant tusks, making it more likely that quality DNA will be available for mammoth cloning.

April 28, 2014

A growing number of geneticists, wildlife biologists and conservationists believe that "de-extinction" — or bringing back an extinct species, such as the woolly mammoth, via cloning — is a very real possibility, and one that is not far off.

Margaret Foster Riley, a law professor at the University of Virginia and director of Law School's Animal Law Program, has recently been researching the topic of de-extinction and weighing its potential ethical and legal ramifications.

Riley, who has written and presented extensively about biomedical research, genetics, reproductive technologies, stem cell research and animal biotechnology, discussed her views on the possibilities and potential ethical quandaries related to reviving extinct species.

Is it feasible that geneticists could clone extinct species, like woolly mammoths? How far away is the technology?

It is feasible, although not yet. Generally the technology that we already have for cloning animals — and we're already able to clone complex species like pigs, sheep and cows, even on a semi "industrial" scale — could be used to clone extinct species. Scientifically, the major limiting factors are the quality of available DNA, the availability of compatible eggs from existing species, and the availability of a compatible animal to gestate the cloned embryo(s). Then, of course, all of those factors have to be coordinated to work together. DNA decays over time even in ideal situations, so the longer a species has been extinct, the less likely it is that we'd have quality DNA. At this point, despite the "Jurassic Park" films, it doesn't look possible to clone dinosaurs — they've been gone too long. Woolly mammoths became extinct about 4,000 years ago and virtually intact animals have been found in frozen tundra. (One reason we've been finding so many mammoths recently is that people are digging them up for their tusks — as a "legal" alternative to elephant tusks.) That makes it more likely that quality DNA is available. But 4,000 years is a long time. Even frozen, it is likely that the DNA has degraded. So to clone a mammoth, scientists may have to try to knit the genomes of many mammoths — perhaps combined with elephant genomes — together to create a viable one. We don't have that technology ready now. And it is still not easy to clone an animal, especially one that is extinct, even if we have quality DNA. We have not yet succeeded in cloning animals that have been extinct for decades — never mind millennia. Last year, some Australian scientists announced that they had successfully created some early-stage embryos of a frog that had become extinct in 1985. It was an important scientific breakthrough, but it's also important to note that none of the embryos survived very long. So we're still a long way from producing a complex mammal that has been extinct for a long time like a woolly mammoth.

Mimi Riley
Professor Mimi Riley says science could get ahead of the legal and ethical considerations involved with cloning.

What do proponents feel could be gained by bringing back the woolly mammoth or similar extinct species? And what are the downsides?

I think woolly mammoths are a popular animal to discuss in the context of de-extinction potential because they have captured the public's imagination. In Russia, they have become a symbol of national heritage. More globally, we like elephants, and woolly mammoths look like furry elephants — so what's not to like? But of course, no one has ever seen a living woolly mammoth. We think we have ideas of what they'd be like, but those may not be accurate — and they are almost certainly not the kind, furry animals that exist in cartoons. But you do hear talk of creating woolly mammoth zoological parks, and that is probably the popular fantasy.

At least for now, the real benefit of this technology is for very recently extinct animals, or animals on the verge of extinction. This could allow us to bring back or maintain species better. In addition, working with species de-extinction is likely to yield considerable scientific knowledge. That knowledge may benefit existing animals or humans. To do this science, you need to learn a lot about genetics and embryonic development. That could yield benefits that are quite indirect. And there may be benefits that we can gather from the animals themselves. One reason the Australian scientists were interested in cloning the extinct frog was because it swallowed its eggs and gave birth orally. Understanding the science behind that could actually yield information that might treat human gastric ulcers.

What sort of legal and ethical questions does this possibility raise?

It's not clear that it's ethical to bring back a species if it will only exist in a zoo-like environment. So some of the questions we have to address are also whether we're willing to rehabilitate habitats for these animals. And when you're talking about a woolly mammoth, we don't know what that habitat is. At a minimum, you're possibly talking about a very large range. In many of the countries that have elephants, we're running out of viable space for them.

Another big problem you'd have in bringing back woolly mammoths is that you'd need to gestate them in elephants. Elephants are an endangered species. In the United States, under the Endangered Species Act, I don't think it would be legal to use them for this purpose. When we were learning how to clone sheep, pigs and cows, it took many pregnancies to produce a living cloned animal. With elephants that is legally untenable in many countries and raises ethical issues in all countries.

One thing that is important to realize, though, is that this is a global enterprise. If you don't like it, you're not going to make it go away by banning it in the United States. And unless the technology raises potential health issues through some sort of zoonotic disease, you're not likely to get a global legal response. If it is technologically possible, someone will do it somewhere if they can find the funds to do it. I don't think law — at least in the context of bans — has the answers here. It is much better, and I think this is happening with programs like de-extinction conferences, to get scientists, ethicists — and lawyers — together to discuss the issues that this science raises and what the appropriate responses should be. That will help keep the science from getting ahead of the ethics.

Harvard Medical School professor and geneticist George Church said recently that cloning Neanderthals is also a very real possibility. What ethical questions do you see being raised by this?

Neanderthals became extinct about 30,000 years ago, so all of the technological problems you have with woolly mammoth DNA would exist and be even more difficult. And I think we've found a lot more mammoth carcasses than Neanderthals. One interesting piece is that there is evidence of human interbreeding with Neanderthals — so it's at least theoretically possible that you might be able to derive a fair amount of Neanderthal DNA from human samples. But most likely you would still have a human-Neanderthal hybrid.

Regardless, Neanderthal de-extinction raises huge ethical issues because they are so closely related to humans. While many (but not all) people are comfortable with human uses of animals, it becomes a different story when you start talking about "creating" a being that is almost human. This is not a new ethical dilemma — it's what the Frankenstein story is really about. But we still haven't found a solution that makes such a creation ethically permissible.

Faculty Q&A Archive


Founded in 1819, the University of Virginia School of Law is the second-oldest continuously operating law school in the nation. Consistently ranked among the top law schools, Virginia is a world-renowned training ground for distinguished lawyers and public servants, instilling in them a commitment to leadership, integrity and community service.

News Highlights