This post has been cross-posted from the OUP blog.
Sharon Levy is a freelance science writer who specializes in making natural resource and conservation issues accessible for a broad audience. She is the author of Once and Future Giants, a book that introduces the idea that Ice Age megafauna extinctions hold important lessons for modern conservation. She lives in Humboldt County, California.
Thousands of years after the last woolly mammoth died, some bioengineers dream of resurrecting the species. When I first heard their arguments, these folks struck me as the modern, high-tech version of snake-oil salesmen. The product they’re promoting is not what they lead people to believe it is, and it won’t do what people like to imagine it will.
Mammoths and mastodons once roamed throughout the Americas, as well as much of Europe and Asia. There were several species, but the best-known is the woolly mammoth, a creature of the far north. Well-preserved carcasses have been discovered melting out of the permafrost in Siberia and the Yukon. There’s been a lot of talk of ‘cloning’ a mammoth by using DNA recovered from bodies preserved in permafrost.
However, the genetic material in even the best-preserved mammoth specimens has been broken to bits, devoured by cold-adapted bacteria and shattered by thousands of years of freezing and thawing. No mammoth sperm cell holding intact DNA—a prerequisite for cloning—has ever been found. Using bits of ancient mammoth DNA, and referring to the genome of living elephants, researchers have pieced together much of the coding genome of the woolly mammoth—the segments that direct the building of proteins. But the vast majority of the genome, whose functions are little understood, remains unmapped.
Still, it’s now theoretically possible to create a pseudo-mammoth. This could be done by taking the genome of an Asian elephant, the closest living relative of the woolly mammoth, and splicing some sequences of mammoth DNA into it. This hybrid DNA could be inserted into an elephant sperm cell, which could then be used to artificially inseminate a female elephant. If the embryo developed and was carried to term, a mammoth-like animal would be born. This is a big ‘if’, because elephant reproduction is slow and complex. Even in efforts to clone living animals, there are often multiple abortions before a live infant is born. And those babies often don’t live long.
“We’d propose to make a hybrid elephant with the best features of modern elephants and of mammoths,” George Church said at a recent TEDx conference on De-Extinction. A genomics pioneer based at Harvard, Church is a master of genetic manipulation. His motivation for trying to raise the mammoth is obscure. When I spoke with him a couple of years back, he told me, “You can be very fussy and insist on getting the genome exactly right. Or you can go for something that has the main visible characteristics: the hair, the size, the tusk shape.” So, like many who imagine mammoths once again roaming the far north, Church was hung up on appearances.
Experiments using ancient mammoth DNA sequences have shown that these cold-adapted elephants had a different form of the blood protein hemoglobin compared to their modern cousins. Mammoth hemoglobin, which picks up oxygen in the lungs and offloads it in the tissues, was designed to release oxygen under cold conditions, a feat that modern elephant hemoglobin can’t perform. So a gene for cold-adapted hemoglobin is now on Church’s list of characteristics to splice into a mammothified elephant. But how many other subtle factors made the mammoth what it was? To believe that human technology can fabricate an animal that will fill the lost niche of the mammoth takes a lot of blind faith—or hubris.
Mammoths lived in cold, dry prairies, an Ice Age habitat that Palaeoecologists call the mammoth steppe, and that once covered great swathes of the planet. Today, the mammoth steppe has vanished. So if bioengineers managed to produce pseudo-mammoths, they’d likely have no place to go. With a lot of luck, they might help to create their own habitat. Ecologist Sergei Zimov is running a long-term experiment in northeastern Siberia which he calls Pleistocene Park. His goal is to bring large herbivores into the soggy tundra in the hope that their grazing will transform the landscape back into the productive grassland that existed in the days of the mammoth. Large herbivores can shape their own habitats, a phenomenon that’s been observed in African savannas as well as in the Arctic. Zimov has seen some signs of success with horses and muskoxen. But whether mammoth-like animals could survive there is unknowable.
While some dream of raising the mammoth, living elephants are under siege. Poaching has reached a new peak; 62 percent of forest elephants in Central Africa were killed for their ivory over the last decade. (It’s worth noting that mammoth tusks were considerably larger: meaning a bigger pay-off of ivory for every animal killed). Elephants often die in clashes with subsistence farmers in Africa and Asia. They need large stretches of habitat to survive, and land unoccupied by humans is becoming a rare and precious resource.
Even bringing back species that were deliberately wiped out in much of North America within the last century remains controversial. The reintroduced gray wolf population in Yellowstone National Park is by many measures a great success: the animals thrived, and have helped to restore an array of other creatures, from beaver to songbirds. Still, as the wolf population has expanded beyond the park’s boundaries, they’ve been met with outrage and gunshots. Yellowstone’s bison, the last free-roaming herd in the United States, gets the same reaction when the animals migrate out of the park in winters of heavy snow.
Conservation efforts for these living megafauna are chronically under-funded. So it’s hard to take the notion of raising a pseudo-mammoth, or any other long-extinct species, as a serious conservation move. The mammoth has been a favorite for resurrection, not because the idea is practical, but because the lost creature has such a strong hold on our imaginations.
Still, it’s probably not fair to compare all advocates of this idea to snake-oil salesmen. After watching a number of speakers at the TEDx De-Extinction conference passionately describe their dreams of raising not only the mammoth, but the thylacine and the passenger pigeon, I think many of these people are sincere. They believe they can raise dead species, and set them free to function in the wild. But they’re so focused on this vision that they seem disconnected from the reality of here and now.