Mammoth resurrection may be a climate solution. Should it be?

Asian elephant in an enclosure at the National Zoo.

An Asian elephant stands near the fence of its enclosure at the National Zoo in Washington DC. Asian elephants are the closest living relatives of wooly mammoths. Photo from 5/8/2019. (Skylar Epstein/George Washington University)

Nearly two decades after "Jurassic Park," a film about resurrecting dinosaurs for a theme park, made millions at the box office, a startup claims it can bring back a different ancient, extinct animal: the mammoth. 

The men behind the biotech startup Colossal Biosciences don’t want to bring back the species to stock a prehistoric theme park. Instead, they claim their “functional mammoths” will be a powerful tool in the fight against climate change. This venture not only raises the question of how science can resurrect a long-dead species... but should it?

The tools to build a new breed of mammoth

Colossal Biosciences, which was co-founded by Harvard geneticist George Church and tech entrepreneur Ben Lamm, claimed to have received $15 million in investment as of September 2021. According to the founders, their team can develop “functional mammoths” within six to seven years.

Lamm stressed that these new mammoths would not be genetically identical to those that lived during the Pleistocene epoch 11 thousand years ago or even the remnant populations that died out 4 thousand years ago. They would be hybrids of mammoths and their closest living relatives, Asian elephants. The genomes of these hybrids would be created by combining genetic material from frozen mammoth carcasses with elephant DNA. 

“They’re not 100% and so think of it almost like a dog breed,” Lamm said. “You got your purebreds and you got –– like what I have –– rescues.” 

Asian elephants and wooly mammoths share about 95.8% of their mitochondrial DNA. The genetic similarities allow Colossal to use genetic material from Asian elephants to build the functional mammoth genome using what Church calls “genome engineering tools.” He compared the approach to those currently being tested to grow organs in pigs that are more compatible to be transplanted into humans. In this case, scientists would work to incorporate mammoth cold tolerance traits, including cold-tolerant hemoglobin and shaggy coats, from mammoth DNA into Asian elephant embryos.

In terms of mammoths, Church described the potential process like this: elephant cells would be edited, in petri dishes away from live animals, to carry mammoth genetic material in each cell’s nucleus. The cells’ nucleuses would later be extracted and implanted into an elephant embryo. The embryo would then be fertilized through in vitro fertilization and grown in artificial wombs.

Colossal has determined that elephants would not host these embryos for both practical and moral reasons, as Asian elephants are an endangered species with a 18-22 month gestation period. While there are limited numbers of potential elephant surrogates, the artificial wombs would allow the program to scale over time as more wombs are created. Church said they also intend to produce embryos and sperm from stem cells. 

The Arctic elephant in the room: should we bring back mammoths?

Talking about the science behind Colossal’s mission avoids the Arctic elephant in the room: should we be bringing back mammoths? DJ Schubert, a wildlife biologist and conservationist with the Animal Welfare Institute, is skeptical.

“The question is not whether it can be done –– but whether it should be done,” Schubert said. “And, from my perspective, I think we have enough species that are currently in dire conditions that we should be focusing our conservation efforts and our conservation dollars on saving those species.”

Schubert expressed frustration that $15 million was invested to bring back the mammoth and argued resources should be spent protecting modern megafauna. He was also concerned that scientists may not have considered the morality of species resurrection, worrying about the fairness of reviving an animal to cage it. 

“Let those species rest in peace and instead let's focus our efforts on preserving what still remains,” he said. 

Colossal pushes back against these criticisms. According to Church and Lamm, Colossal’s goal is not to develop functional mammoths out of pure curiosity, but to fight climate change and develop technologies with applications including conservation.  

Stomping out greenhouse gases

Church hopes the first Arctic elephants will not live in captivity but in a preserve such as Pleistocene Park, an experimental nature preserve in the Russian Arctic that is recreating the mammoth-steppe ecosystem. According to the park’s current director Nikita Zimov, the project seeks to restore this ecosystem through the reintroduction of animals in the hopes of fighting climate change through grassland creation and permafrost preservation. 

Zimov said his father came up with the idea during the Soviet era and his family has been working on the project since 1996. The Pleistocene Park concept predates the blockbuster that inspired its would-be name. But unlike Jurassic Park, Pleistocene Park is not meant to be a theme park. 

According to Zimov, it's intended to be a self-expanding ecosystem large enough to impact the climate and provide habitat to millions of animals. Currently the preserve is only 144 square kilometers, but numerous native and exotic species have been introduced including reindeer, Yakutian horses, moose, bison, musk ox, yaks and Kalmykian cows. According to Zimov, the mammoths would transform the park and fight climate change by toppling trees and trampling snow.

While this may seem counterintuitive, Zimov explained the apparent paradox. 

“If you come to the Arctic, the effect of planting trees (to store carbon) is not that great,” Zimov said. “Trees are sparse, small, and they grow extremely poor(ly).” 

The deep root systems of fast growing Arctic grasses are more effective at storing carbon in the Arctic environment than the trunks of slow growing trees. The mammoth’s propensity for toppling trees would expand the grassland ecosystem more quickly than would otherwise be possible, and allow for more carbon to be stored.

The mammoths would also preserve permafrost, the layer of subsurface Arctic soil that has remained frozen for many millennia. As rising global temperatures melt permafrost, it releases hundreds of thousands of years of methane, a greenhouse gas that is 25 times as potent as CO2. Scientists worry this will start a positive feedback loop and hasten global warming. 

The permafrost in the soils of the Arctic contain 1,460-1,600 billion metric tons of carbon, about twice as much as currently contained in Earth’s atmosphere. The release of all this carbon by melting permafrost would be disastrous for global ecosystems and human civilization. 

Cooling permafrost will prevent methane emissions. This is where Pleistocene Park’s animals come into the picture. Zimov said permafrost is heated during the summer but cannot cool during winter because the ground is buried beneath snowfall, which has increased due to climate change. 

“This snow is acting as a heat insulator and that's why permafrost is five degrees warmer than (the) temperature of air,” Zimov said. “If you would now remove the snow entirely very quickly, within several years, the temperature of permafrost would be going down.” 

Zimov said grazing animals protect permafrost by removing the thick layer of snow to access the food underneath. The snow is compacted during the foraging process making it a much less effective insulator than thick, undisturbed snow. Once the thick snow has been cleared, the temperature of the permafrost beneath the ground drops.

Mammoths could trample snow especially effectively because of their size and the amount of food they would eat.

When asked about the project’s climate benefits Schubert of the Animal Welfare Institute said that the project should continue using extant animals for the project, not extinct species.

“I have nothing against anyone thinking outside the box because I think that's what is going to be necessary to frankly save this planet,” he said. “I just think that if they're seeing success using these proxy animals, I think they should use these proxy animals… (instead of) trying to bring back animals that have long since been dead.” 

A future of technologically-enabled conservation

Lamm said he hopes the genetic tools and artificial wombs being developed for mammoths will help preserve other species. He compared the development of Arctic elephants to the Apollo missions in terms of its potential for spinoff technology. He even expressed the hope that there may soon be the technology for 50 rhino calves to be brought to term in a lab at a time before release into the wild. 

“We hope that (this) will be relevant to many other endangered species as well,” Church said. “The focus is on endangered species and environmental impact that would be helpful to humans; it's not about de-extinction.”

Even Schubert expressed optimism about using Colossal’s technology to help contemporary species, especially those that are currently endangered. Still, Schubert said the best way for humans to protect species is to address why they became endangered; only then should genetic solutions be considered.

In "Jurassic Park," scientist Ian Malcolm chastises billionaire John Hammond for creating dinosaurs, saying, “Your scientists were so preoccupied with whether they could, they didn't stop to think if they should.” Now, we are having that debate in real life about mammoths. If nothing else, the fact that we are having this debate is a step forward. 

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