GENETIC REWILDING – DE-EXTINCTION – ANIMAL WELFARE – CONSERVATION GENETICS – BIOETHICS
When three snow-white wolf pups were announced to the world on April 7, 2025, Colossal Biosciences declared: ‘The first de-extinct animals are here.’ Fourteen months later, Romulus, Remus, and Khaleesi are fully grown, living as a coordinated pack on a secret 2,000-acre preserve in the United States, hunting together, howling with a sound not heard on Earth for over ten thousand years — and at the centre of a scientific and ethical controversy that has only deepened. The question is no longer whether the technology works. The question is what the technology actually did, and what it means for conservation, genetic science, and the ethics of creating life.
How Colossal Built Its Wolves
Colossal Biosciences is a Dallas-based biotechnology company founded in 2021 with the stated goal of reversing extinction. Its flagship projects include the woolly mammoth, the Tasmanian tiger, and the dodo. The dire wolf — Aenocyon dirus, an apex predator of the Pleistocene that vanished from North America approximately 10,000 to 13,000 years ago — became the first species Colossal claimed to have actually de-extincted.
The technical process was audacious. Scientists at Colossal extracted ancient DNA from two dire wolf fossils: a 13,000-year-old tooth found in Sheridan Pit, Ohio, and a 72,000-year-old ear bone unearthed in American Falls, Idaho. They sequenced the dire wolf genome from these samples, compared it with the grey wolf (Canis lupus) genome, and identified 20 edits across 14 genes encoding the dire wolf’s defining characteristics — larger size, broader skull, more powerful jaws and shoulders, white coat, and distinctive vocalizations.
Rather than conventional tissue biopsies, Colossal used a less invasive approach: isolating endothelial progenitor cells (EPCs) from grey wolf blood. These cells were edited at 20 targeted genomic positions. Critically, no ancient dire wolf DNA was physically spliced into the grey wolf genome; instead, the grey wolf genes were rewritten at those positions to match dire wolf sequences. The edited nuclei were then transferred into denucleated egg cells from domestic dogs — somatic cell nuclear transfer, the same fundamental technique used to clone Dolly the sheep in 1996. Of 45 engineered ova produced and implanted into two large dog surrogates, two embryos took hold. The pups were delivered by planned caesarean section. Romulus and Remus were born October 1, 2024; Khaleesi on January 30, 2025.
George Church, Colossal co-founder and professor of genetics at both Harvard and MIT, described the EPC platform as ‘a game changer’ for its efficiency and low invasiveness. Beth Shapiro, Colossal’s Chief Science Officer, has stated: ‘I think they are the luckiest animals ever. They will live their entire lives on this protected ecological reserve. They’re not capable of living in the wild, and we want to study them for their lives.’ Their location remains secret.
“No ancient dire wolf DNA was actually spliced into the grey wolf’s genome. The grey wolf genes were rewritten at 20 positions across 12 million letters of genomic divergence.”
One Year On: Fully Grown, Hunting, and Living in Secrecy
By February 2026, the three animals were fully grown and living as a pack. Colossal’s Chief Animal Officer Matt James reported they had completed their first coordinated hunt — initially returning a live rabbit, subsequently mastering the kill — and were now pursuing larger prey including deer. They weighed significantly more than typical grey wolves of the same age. From birth they exhibited wild lupine behaviour: keeping their distance from humans, retreating even from handlers who raised them, beginning to howl at two weeks old. Colossal has confirmed it has no current plans to rewild the animals.
The Scientific Verdict
The scientific community’s response was swift and largely sceptical. The core objection is arithmetical: the grey wolf genome differs from the dire wolf genome by approximately 12 million DNA letters. Colossal edited 20 positions across 14 genes — a vanishingly small fraction of the genomic divergence between two species that separated approximately 5.7 million years ago.
An article in Science described the pups as ‘genetically edited grey wolves’ rather than true dire wolves. Stem-cell biologist Jeanne Loring of the Scripps Research Institute was unambiguous: ‘I don’t think they de-extincted anything.’ The IUCN Species Survival Commission Canid Specialist Group — the world’s foremost authority on canid conservation — issued a formal commentary on April 18, 2025, characterising the animals as ‘a genetic proxy of an extinct dire wolf,’ not a de-extincted species. Ben Novak of Revive & Restore said: ‘This fits the Jurassic Park model beautifully. But it is clearly for spectacle.’
Palaeontologist Tori Herridge, who had declined an earlier invitation to serve as a Colossal scientific adviser, expressed concern about the company’s posture toward criticism: ‘We have a company that is only listening to people who agree with them, who is pushing forward with statements that they aren’t backing down from. This is not really where we want to be with a technology that has the potential to change the way our world will look.’
Colossal’s own chief scientist offered a revealing concession in May 2025: she acknowledged the animals are ‘grey wolves with 20 edits’ and that the term ‘dire wolves’ is a colloquialism, not scientific terminology. Her response to the controversy: ‘If you’re not controversial, you’re not pushing hard enough. If we just stick with what everybody is comfortable with, we’re going to keep the status quo — and we know the status quo is not good enough.’
A peer-reviewed study in Animals (Basel, June 2025) by Azevedo and Magalhães-Sant’Ana used the Five Domains Model to assess welfare risks and reached a pointed conclusion: the engineered animals risk living ‘socially and ecologically constrained lives’; moral arguments for reviving long-extinct species are weak, particularly where extinction was not anthropogenic; and current EU and US regulatory frameworks lack the clarity and scope to classify, regulate, or protect such animals.
“We have a company that is only listening to people who agree with them, pushing forward with statements they aren’t backing down from. This is not where we want to be with a technology that has the potential to change the way our world will look.” — Tori Herridge, Palaeontologist
Welfare Questions Nobody Is Officially Answering
Two animal welfare concerns persist regardless of one’s position on de-extinction. The first concerns the surrogate mothers. Somatic cell nuclear transfer remains, nearly three decades after Dolly, an inefficient and physically burdensome process. Robert Klitzman, professor of psychiatry and director of the bioethics master’s programme at Columbia University, noted: ‘There’s a risk of death. There’s a risk of side effects that are severe. There’s a lot of suffering involved in that. There are going to be miscarriages.’ Colossal’s surrogates did not miscarry — but they represent two live births from 45 engineered ova. The fate of the remaining 43 is not publicly documented.
The second welfare concern is existential for the animals themselves. Wild wolf packs typically number 15 or more, with hunting territories of 50 to 1,000 square miles. Three animals on a 3-square-mile fenced preserve, with no prospect of rewilding, no full social group, and no ecological context in which the dire wolf evolved, cannot live anything resembling a dire wolf’s life. Arthur Caplan, professor of bioethics at NYU Grossman School of Medicine, stated: ‘It has to live somewhere, and it isn’t clear what the environment was that the dire wolf lived in, or what it ate, or sort of its behaviour, and so you kind of face a possibility you won’t know where to keep this animal that you made healthy.’
The Red Wolf Programme
The red wolf dimension of Colossal’s programme is more scientifically defensible and more directly conservation-relevant. The red wolf (Canis rufus), with fewer than 20 individuals surviving in the wild in coastal North Carolina, is North America’s most endangered canid. Its captive breeding programme has lost genetic diversity it cannot recover from existing populations.
Bridgett vonHoldt (Princeton University) and Kristin Brzeski (Michigan Technological University), both Colossal scientific advisers, identified Gulf Coast canid populations whose genomes contain red wolf ‘ghost alleles’ — genetic variants once characteristic of the species, now surviving only in hybrid individuals outside the formal conservation programme. Colossal used its EPC platform to clone four red wolves from these canids, producing what the company calls the first ‘Ghost Wolf.’ The cloned red wolves live in a separate fenced area on the same preserve. No animals have yet been rewilded. Ghost-allele recovery represents a potentially valuable conservation tool, though its real-world impact remains to be demonstrated.
The Regulatory Void
What the dire wolf experiment has most unambiguously demonstrated is that existing regulatory infrastructure — in the US, the EU, and internationally — is wholly unprepared for the realities of commercial genetic rewilding.
A peer-reviewed commentary in Animal Sentience (November 2025) stated plainly: ‘There is little to no existing regulatory oversight for de-extinction efforts. Given considerable public interest in regulating what private entities can do with genetic technologies, public natural areas, and individual animals, now is the time for open discussions of the ethics and legality of these technologies.’ Three genetically engineered animals of uncertain taxonomic status are living at a secret location, created by a for-profit company with celebrity investors including Tom Brady, Tiger Woods, Paris Hilton, and Peter Jackson. CEO Ben Lamm has been candid: ‘We’re not a foundation, we’re not a nonprofit. We are trying to actually develop products and build technologies.’
In February 2026, Colossal announced a biovault in Dubai’s Museum of the Future — the Colossal Biovault and World Preservation Lab, preserving frozen tissue from 10,000 species. It is simultaneously a genuine conservation initiative and a high-visibility brand exercise. The company’s mammoth project is targeting embryo implantation by the end of 2026 and a calf born in 2028, requiring edits to approximately 85 genes in an Asian elephant genome.
“There is little to no existing regulatory oversight for de-extinction efforts. Now is the time for open discussion of the ethics and legality of these technologies.” — Animal Sentience, peer-reviewed commentary, November 2025
What the First Year Actually Tells Us
What does the first year of Romulus, Remus, and Khaleesi tell us? Several conclusions can be drawn with confidence.
The technology is real and advancing. The EPC blood-cloning platform is a genuine innovation. Precision germline editing of 20 positions in a viable animal is a technical achievement. The ghost-allele red wolf programme has legitimate potential conservation value. These accomplishments should not be dismissed because of how they were marketed.
The de-extinction claim is not scientifically defensible as stated. Editing 20 positions across 12 million letters of genomic divergence does not resurrect a species. The IUCN’s characterisation — genetic proxy — is the accurate one. Semantic inflation has consequences: distorted research priorities, misallocated conservation funding, and eroded public trust in the scientific institutions that must govern these technologies.
The regulatory vacuum is the most urgent problem the dire wolf has exposed. Three animals of uncertain taxonomic status live in secrecy with no independent welfare oversight, no public accountability for their long-term care, and no regulatory framework governing what happens if Colossal’s priorities or funding change. This is not a hypothetical risk. It is the current situation.
The conservation opportunity is real but peripheral to what Colossal has achieved so far. The question conservation biology must ask is whether the spectacle economy of de-extinction — with its celebrity capital and media cycles — is the most efficient vehicle for deploying genuinely valuable genomic tools, or whether it absorbs attention and funding that the living biodiversity crisis cannot afford to spare.
Romulus, Remus, and Khaleesi are remarkable animals. They howl with a sound not heard on Earth for over ten thousand years. Whatever they are — grey wolves, dire wolf proxies, novel organisms — their existence raises questions that science, ethics, law, and conservation policy cannot defer. The dire wolf story, in its most consequential dimensions, is only just beginning.
– Vamsi Priya Potharaju
