Thanks to advances in science, the reintroduction of extinct animal species is now feasible — even inevitable. But beyond possible benefits for biodiversity, these projects raise numerous environmental and ethical dilemmas.
PARIS — In 2700 BC, history's first known architect, Imhotep, built the pyramid of Djoser, considered to be the oldest in the world. At about the same time, in Siberia, the last mammoths on our planet were dying out.
Thousands of years later, the species continues to arouse curiosity and fascination. Now, new projects aim to bring the prehistoric animal out of the history books and back to life. Australian cultured meat company, Vow, unveiled a giant meatball made from a wooly mammoth in a laboratory. According to them, this protein ball from the past could pave the way for our food of the future.
On the scientific level, our abilities to recreate species that have disappeared less than a million years ago are now established.
Colossal Biosciences, a start-up founded in 2021 by Harvard geneticist George Church, aims to create elephants with wooly mammoth characteristics. Geneticists hope to eventually integrate their "mammophant" into nature, specifically in the Pleistocene Park, in the extreme northeast region of Siberia.
In the park, Sergei Zimov and his son Nikita have been trying for twenty-five years to recreate the tundra as it was a few hundred thousand years ago during the ice age, with vast grassy plains populated by large herbivores. Reindeer, bison, elk and yaks now roam freely over the 14,400-hectare park.
"With the technical advances of recent years, the possibility of success in 'de-extinction' projects is becoming increasingly plausible," says Lionel Cavin, paleontologist and curator at the Museum of Natural History in Geneva, co-author of Reviving Species?, alongside evolutionary biologist Nadir Alvarez.
This idea, as fascinating as it may be, doesn't make everyone happy. "Technically, it is not enough to succeed," comments Régis Debruyne, a paleontologist at the National Museum of Natural History in Paris, for whom these creatures will always remain "pseudo-mammoths."
To him, these endeavors do not take into account the post-de-extinction period. "Four thousand years ago, the humidification of the climate spelled the end of this species' environment. The mammoth became extinct because the environment in which it had flourished for almost one million years disappeared. How could it survive in the framework it will encounter?" he asks.
A species carries with it the memory of its history.
For the mammoth to survive, it needs to evolve in a steppe environment. However, as the researcher points out, the high latitudes of the Arctic are made up of marshy tundra that is too humid for the animal. "It is a vegetation at ground level that cannot support very large populations of herbivores," explains Debruyne. "We would have to constantly feed and move them to avoid certain death. The idea of recreating the steppe by introducing large herbivores may sound great on paper, but it is an inversion of cause and effect."
The long-term viability of resurrected species is far from sure. In addition to this environmental difficulty, the genetic diversity necessary for the animal's survival is not sought by scientists. According to Debruyne, it is also not possible to create it artificially. And, like humans, these animals rely on generational transmission for their learning. As orphans without a real social structure, their chances of survival would diminish.
"At this point, we can indeed wonder how a mammoth born from an Asian elephant would react. We could have surprises in terms of its reactions," acknowledges Cavin. And without the animals that lived alongside mammoths and played an important role in their physiology, their behavior remains unpredictable.
Overall, bringing back extinct species could be a poisoned gift. Florence Burgat, a philosopher specializing in animal issues and research director at the French National Institute for Agricultural Research, Food and Environment, agrees: "A species carries with it the memory of its history. Imagine that we revive a Neanderthal man. He would be completely lost because he does not have the memory of all this modernity, scientific and technical development that shapes our imagination, our references, who we are. A resurrected mammoth would be even more disoriented than a lion put in a cage."
Scientists from Vow creating the first meatball from mammoth DNA in Amsterdam, Netherlands.
Still, the founders of Colossal have a compelling argument in their favor. As climate change increasingly preoccupies people's minds, they claim not only to have the key to ending species extinction, but also that the mammoth has the ability to slow down the thawing of permafrost, thereby limiting greenhouse gas emissions.
"The permafrost is melting faster and faster because paradoxically, the snow that covers this area acts as thermal insulation. This prevents the soil from staying cool," explains Cavin.
"Colossal's idea is then to send these large mammals to trample the snow in order to slow down the melting of the permafrost and reduce methane emissions," Cavin says. By grazing and creating clearings, the mammoths could also reflect more heat back into the atmosphere through the albedo effect. In short, de-extinction is presented as a means of combating climate change and the biodiversity crisis. "But all of this seems to me to be just a pretext," admits the author. "We're not going to bring back mammoths to save the climate!"
For the project to work, several hundred thousand mammoths would need to be reintroduced to this area. Debruyne sees it as nothing more than a publicity stunt. "The ecological argument doesn't hold up," the paleontologist insists. "The creators of Colossal are simply aware that if they went through the traditional channels of funding for global research, they wouldn't get a penny."
For the majority of scientists, Colossal's environmental discourse seems more like an attempt to legitimize the passions of slightly mad scientists. "At the time, Jean-Paul Renard, the father of cloning in France, used to say in small circles that he had to find an argument to make his research appear legitimate to the public. This is how the idea was invented that cloning would help us better understand high-risk pregnancy issues," says Burgat.
The flip of the coin
Humans are responsible for a sixth mass extinction. In 130,000 years, more than 2.5 million species have disappeared from the world, including 500,000 in just the last 1,500 years. By promising to bring back animals whose extinction we may have caused, the company is touching a sensitive nerve. It could be the solution to disappearing species, but it is difficult not to see the downside.
"By trying to make us believe that we will solve biodiversity problems in this way, we risk encouraging daily inaction," says Debruyne. "The creation of genetic arks leads us to believe that we can continue at the current pace, since we will simply have to bring back to life the species that we have destroyed!"
In 2017, a study published in the scientific journal "Nature Ecology & Evolution" estimated the cost of reintroducing the Chatham Island bellbird, a bird extinct in New Zealand, to be $360,000 for the first year alone. The same document states that preserving extinct species would require three to eight times more money than for threatened species.
Colossal, on the other hand, boasts of having raised over $75 million, thanks to major donors such as Paris Hilton and Thomas Tull, the former CEO of the production company behind the 2018 film "Jurassic World: Fallen Kingdom." These figures raise questions about the financial priorities given to the living world.
A regulatory framework would need to consider the limits of de-extinction.
Rather than rushing to the aid of biodiversity, these projects could have the opposite effect of maintaining the status quo. The coexistence of this desire to bring back a vanished past while continuing to see current species disappear seems paradoxical.
Burgat sees it as a vicious circle: "Just look around you to marvel at this animal life that is both so close and so different from us. Yet, it seems as if animals that have been extinct for thousands of years are the real individuals likely to catch our attention."
Cavin is less alarmist, and calls for caution in balancing preservation and de-extinction. "The topic is obviously very sensitive," he acknowledges. "But if used properly, this process could become a means of encouraging biodiversity protection. The essential thing is that it does not compete with environmental protection, which must remain the priority."
This suggests the need to rethink the legal framework in which these projects operate. Currently, regulations are either absent or minimal. A regulatory framework would need to consider the limits of de-extinction, the future and life of resurrected species and the geographical areas involved. More importantly, according to Debruyne, future legislation will need to determine whether animals resurrected by Colossal will be defendable as biological organisms or as products patented by the start-up.
The world's first mammoth meatball, made from the extinct giant's DNA, has been unveiled at Nemo Science museum in the Netherlands.
The revolution of molecular scissors
On July 30, 2003, Celia 2 was born in a Spanish laboratory. This little Pyrenean ibex, which lived less than ten minutes, became the first subspecies to be resurrected by science, two years after the disappearance of its last representative, Célia, during a storm. Cells from her skin had been used to clone her and bring her back to life. The idea was to retrieve the nucleus of a cell from the extinct animal and integrate it into the ovum of a close species, which acts as a surrogate mother.
"This method remains complex because it suggests using well-preserved genomes," explains paleontologist Cavin. "However, for species that have been extinct for a certain number of years, these genomes are sometimes in poor condition."
Recently, attempts to revive the Christmas Island rat in the Indian Ocean have failed. But since 2012, researchers have had a new tool: the CRISPR-Cas9 complex. These "molecular scissors" allow DNA to be cut at a precise location in the genome, thereby invalidating or correcting a gene. At Colossal, scientists have made it their mission to modify Asian elephant cells by adding mammoth genes. The genome is then implanted into a female elephant. "So they will never be exactly the same genes," says Cavin. "But we will have an elephant with the characteristics of the wooly mammoth, with highly developed tusks, long hair, and resistant to the cold."
A societal choice
The debate around de-extinction is symptomatic of our relationship with the rest of the living world. After all, isn't playing the role of mad scientists to bring species back to life a new form of domination over biodiversity?
Not necessarily, says Cavin: "We have always tinkered with the genes of the plants and animals around us through artificial selection. We have made entire megafauna disappear. Only in Africa, where humans have co-evolved with large mammals, is the situation not yet catastrophic." While we have spent the last hundreds of thousands of years protecting ourselves, and therefore separating ourselves, from the wild world, Cavin prefers to talk about "care" rather than "domination."
When Cavin started his investigation with colleague Nadir Alvarez, he was convinced he would write a critical book against this project. He admits that, over the course of his research, his opinion has become more nuanced: "In the majority of cases, we do indeed consider that (de-extinction) is not the best solution. But in certain situations, it could be interesting to consider."
Among those cases could be species driven to extinction by humans, he says. While he emphasizes the importance of prioritizing environmental protection, he believes that it could be possible to link de-extinction projects with obligations for rewilding.
It is a matter of defining, together, our society for the future.
The thylacine, or Tasmanian tiger, a marsupial mammal that disappeared in the 1960s due to hunting, represents for him a more legitimate choice than that of the wooly mammoth. Since some of these individuals are preserved in alcohol in museums, it would be possible to recover its genome and reintegrate them in Tasmania. It could then become an "umbrella" species, whose protection leads to that of many other animals and plants, like the panda today.
The nonprofit "Revive & Restore" sees in the possible resurrection of passenger pigeons, which damage the canopy of forests in their path, the possibility of recreating ecological niches that host a large number of species of insects, reptiles, and birds.
Burgat, on the other hand, insists it's more important to protect species that are still alive. "Here, we propose to kill one and resurrect another," she says.
"In any case, these technical advances will happen no matter what. So we might as well think about them early enough and try to use them well," says Cavin. Ultimately, these projects aim to lay the groundwork for the debate. It is a matter of defining, together, our society for the future.