DIRE WOLVES, WOOLLY MAMMOTHS AND DODOS, OH MY! The “De-Extinction” Controversies
Image by author using Microsoft Designer
INTRODUCTION
From dire wolves to woolly mammoths to dodos and beyond, talk of reversing extinction — “de-extinction” — is no longer confined to the pages of fiction. Scientific advancements, growing awareness of biodiversity loss, significant financial investment, public fascination, and the potential for conservation and medical applications have collectively accelerated the interest in de-extinction. But, what does it mean, can we do it, and, if so, should we?
How common is extinction?
Before exploring de-extinction, let’s briefly look at extinction. It has been a constant feature of Earth's history, driven by natural evolutionary processes and catastrophic events, resulting in an estimated 99.9% of all species that ever lived becoming extinct. Watch out humans!
Recently, our activities — habitat destruction, overexploitation of resources, pollution, invasive species introduction and human-caused climate change — have pushed species to the brink at a pace hundreds to thousands of times faster than the natural background rate.
What is de-extinction?
Its meaning may seem obvious, but de-extinction is not defined by federal or international law and has no official definition. Heated battles are being waged over its meaning. The general public would probably loosely define it as bringing back to life a genetically identical animal that has died out. However, even current cloning de-extinction procedures cannot produce a genetically identical animal, as the necessary living surrogate mother contributes her own mitochondrial DNA.
Perhaps the most authoritative definition of de-extinction is in the Guiding Principles on Creating Proxies of Extinct Species for Conservation Benefit (“Guidelines”) issued in 2016 by the Species Survival Commission (SSC) of the International Union for Conservation of Nature (IUCN). The SSC is a well-respected, vast, global, science-based network of over 10,000 volunteer experts dedicated to providing information, advice, and policy guidance to the IUCN and others on biodiversity conservation.
Before defining de-extinction, the Guidelines briefly address its misleading implications:
The term “de-extinction” is misleading in its implication that extinct species, species for which no viable members remain, can be resurrected in their genetic, behavioural and physiological entirety. These guidelines proceed on the basis that none of the current pathways will result in a faithful replica of any extinct species, due to genetic, epigenetic, behavioural, physiological, and other differences.
The Guidelines then define and distinguish de-extinction and “proxy:”
Proxy is used here to mean a substitute that would represent in some sense (e.g. phenotypically, behaviourally, ecologically) another entity – the extinct form. Proxy is preferred to facsimile, which implies creation of an exact copy ….
For the purposes of these guidelines the legitimate objective for the creation of a proxy of an extinct species is the production of a functional equivalent able to restore ecological functions or processes that might have been lost as a result of the extinction of the original species.
“De-extinction” is therefore here used in a limited sense to apply to any attempt to create some proxy of an extinct species or subspecies (hereafter “species”) through any technique, including methods such as selective back breeding, somatic cell nuclear transfer (cloning), and genome engineering ….
Where possible the term “proxy” will be used to avoid the connotations of “de-extinction”.
So, in summary, the Guidelines define de-extinction as any attempt to create a substitute in some sense for an extinct species or subspecies, with the qualification that, for the Guidelines, the objective for creation of the substitute must be to “restore ecological functions or processes that might have been lost as a result of the extinction of the original species.” This article attempts to use “de-extinction” and “proxy” as defined in the Guidelines.
Was the Dire Wolf recently de-extincted?
In April 2025, Colossal Laboratories and Biosciences announced with great fanfare that it had de-extincted the dire wolf, which became extinct about 10,000 years ago and achieved significant recent fame due to its prominent role in the popular "Game of Thrones" television series. Prominent magazine covers and article headlines heralded the return of the dire wolf.
Those announcements were exaggerations. In summary, Colossal created three genetically modified modern gray wolves that express selected traits reminiscent of dire wolves, but are not dire wolves. In more detail, here’s the process Colossal used:
● Ancient DNA Analysis: Colossal extracted ancient DNA from dire wolf fossils—a 13,000-year-old tooth and a 72,000-year-old ear bone—to identify genetic differences between dire wolves and gray wolves. Their DNA is 99.5% the same, but, given the size of their genomes, there are thousands of differences.
● CRISPR Gene Editing: Using CRISPR technology, scientists made 20 edits across 14 genes in gray wolf cells to emulate selected key traits associated with dire wolves, such as larger body size, broader skulls, and paler coats.
● Embryo Development and Surrogacy: The edited gray wolf cells were used to create embryos, which were implanted into domestic dog surrogates, resulting in the birth of three pups: Romulus, Remus, and Khaleesi. One other died.
● Resulting Offspring: These pups exhibit certain dire wolf-like characteristics (large size, whitish coat color and jaw structure), but are genetically modified gray wolves, not actual dire wolves, due to the limited number of genetic edits relative to the full genomic differences between the species. The pups also have a small amount of the surrogate dog’s mitochondrial DNA.
Despite its limitations, Colossal’s work is a significant scientific accomplishment. It’s the first time scientists have combined ancient DNA analysis, targeted gene editing, and novel cloning techniques to create living animals engineered to closely resemble an extinct species.
What’s happened to the three Colossal wolves?
They are kept in a 2,000 acre fenced undisclosed location, where they are very well cared for given their unnatural surroundings. They will not be allowed to breed. Colossal does not plan to release them. You can see images of them on Colossal’s site.
Has the IUCN commented on Colossal’s alleged de-extinction of the dire wolf?
Yes. The IUCN Species Survival Commission (SSC) Canid Specialist Group issued an assessment, which concluded that the animals produced by Colossal are neither true dire wolves nor valid proxies under the Guidelines. It emphasized that the genetic modifications made were limited to a few genes and there is no evidence that the pups phenotypically resemble the dire wolf. Furthermore, it expressed concern that such projects might mislead the public and divert attention from conserving existing species.
In a preemptive response to the IUCN’s anticipated critique, Colossal issued a detailed statement arguing that Colossal’s dire wolf de-extinction project aligns with the Guidelines, emphasizing that its primary goal is not ecological replacement but the development and rigorous assessment of advanced conservation technologies, such as multi-gene editing and veterinary protocols, that can benefit endangered canids and broader conservation efforts.
What other proxies for extinct animals are being pursued?
With the qualification that their release plans are in the indefinite future, several companies are trying to create proxies of other animals. For example, Colossal is actively pursuing a proxy of the woolly mammoth, having achieved the creation of gene-edited "woolly mice" — yes, you read that correctly — with mammoth-like traits as a significant proof of concept step in their research and development process towards their goal of producing a woolly mammoth-like elephant hybrid by 2028. It’s also working on a dodo proxy. Revive & Restore, a biotechnology and conservation non-profit, is working to create a proxy of the passenger pigeon by using gene-editing techniques on its closest living relative, the band-tailed pigeon, to produce birds with key passenger pigeon traits by 2032. If you were wishing to hear that T-Rex is on someone’s list, sorry, it’s DNA is way too degraded to be recovered.
What are the arguments for de-extinction efforts?
Common arguments include the following:
○ Extinct species often played vital roles in their ecosystems. Reintroducing them could help restore ecological balance, revive natural processes, and even increase biodiversity. For example, the reintroduction of wolves to Yellowstone National Park had significant positive effects.
○ Humans have directly or indirectly caused the extinction of many species. Some argue that we have a moral obligation to try to reverse this damage and restore the balance of nature.
○ De-extinction research can lead to breakthroughs in genetics, developmental biology, and reproductive technologies. These advancements could also be applied to conserving currently endangered species, such as restoring genetic diversity in small populations or curing genetic weaknesses. Colossal uses methods developed in its de-extinction work to help prevent the extinction of the red wolf, a critically endangered species, and other living animals. Colossal, which partners with several conservation groups, plans to offer its techniques to conservation and government groups for free. The IUCN’s assessment of Colossal’s dire-wolf project acknowledges that: “Gene editing technologies may offer specific benefits to species survival, such as removing harmful mutations or increasing genetic diversity in small, inbred populations, and even potentially reviving ancestral variation lost in living populations today.” But, in an apparent slap at Colossal, it adds: “However, presenting this technology as a ready-to-use conservation solution is premature ….”
● Inspiration and Public Engagement:
○ De-extinction efforts can generate public excitement and support for wildlife and conservation efforts.
● Potential Economic Benefits:
○ De-extincted animals could create new tourism and research opportunities, generating economic benefits.
What are the arguments against de-extinction efforts?
Typical arguments include the following:
● Playing God:
○ Some argue that de-extinction is an unnatural human intervention that disregards the natural processes of evolution and extinction, potentially leading to unforeseen, negative Jurassic Park-ish consequences. (Advocates of de-extinction respond that we’ve already been playing God by causing extinctions and otherwise mistreating our animal kin.)
● Resource Allocation and Prioritization:
○ Many, such as the IUCN, argue that the significant financial and scientific resources required for de-extinction would be better spent on preventing the extinction of the many endangered species. Focusing on de-extinction could divert crucial funds and efforts from addressing the root causes of extinction, such as habitat loss, climate change and pollution. (Colossal responds that it has explicitly drawn in unique funding sources dedicated to conservation innovation, ensuring traditional conservation funding streams remain unaffected.)
○ Some worry that de-extinction could create a perception that extinction isn't truly forever, reducing the urgency to protect existing species or creating an excuse for those who don’t care to do so. The Trump administration has already praised Colossal’s work on the dire wolf as an example of why it claims fewer conservation regulations and more innovation, including under the Endangered Species Act, are appropriate. Unfortunately, while not explicitly arguing for that goal, Colossal gave credence to it by posting that praise on its website.
● Ecological Concerns and Unpredictable Consequences:
○ Ecosystems have changed significantly since the extinction of many de-extinction targets. Reintroducing them into modern environments could have unpredictable and potentially harmful consequences for existing species and the overall ecological balance. De-extinct animals might become invasive, outcompete native species, or be unable to adapt to the altered habitat.
● Animal Welfare and Ethical Issues:
○ De-extinction raises serious animal welfare and ethical concerns, as the cloning and genetic engineering involved can lead to high failure rates, suffering in surrogate animals, and health problems in the resulting offspring. Reintroduced animals may struggle to survive in modern ecosystems that differ vastly from their original habitats and may lack the social learning and environments necessary for normal development, potentially resulting in captivity, disease vulnerability, and isolation. Critics also question the moral logic of reviving species when many existing animals continue to suffer from inadequate treatment and protection.
● Suspicions about Colossal’s Entrepreneurial Efforts:
○ Many observers harbor significant suspicions about Colossal’s de-extinction motives, suggesting its mission is driven less by conservation and more by profit and publicity. They cite its for-profit status, 10.2 billion dollar valuation, billionaire co-founder Ben Lamm, entrepreneurial business model, and roster of celebrity investors. As a New Yorker writer wrote: “No one is going to confuse Colossal with the Sierra Club.”
Most conservation groups and relevant scientists who have expressed opinions oppose or are skeptical of de-extinction efforts for some or all of these reasons.
Conclusion
The de-extinction work by Colossal is fascinating. I encourage you to review its detailed and elaborate website and other linked materials. After having reviewed substantial information over the last couple of months, I acknowledge some potential benefits of de-extinction efforts, and, if they go forward, I hope those benefits materialize. But, for what it’s worth, I find the arguments against de-extinction more persuasive.
Frank Brown, UU of Arlington, Va.