by Jim Heffelfinger - Friday, May 9, 2025
Colossal Biosciences, a Texas-based biotechnology company, recently announced that it brought back the dire wolf from extinction. It touted this achievement as the first “de-extinction.” Anyone in the world living within 100 yards of electricity has heard this amazing story. “Game of Thrones” fans, put away your fur-lined capes because extinction really is forever.
What is a Dire Wolf?
Because of popular culture, most people don’t have an accurate view of what a dire wolf really was. The dire wolf probably originated in North America, first showing up in the Pleistocene and then becoming extinct when all its large mammal prey disappeared around 13,000 years ago. Despite their scientific name Aenocyon dirus, meaning a “dreadful” wolf, they were about the same size as Canadian wolves, but with a broader and more powerful skull. We know a lot about how they differed from gray wolves because the famous La Brea Tar Pits contained 4,000 specimens and even today you can visit a wall display of 404 dire wolf skulls. A study in 2006 showed that gray wolf and dire wolf skulls differed in only four out of 15 measurements compared. A mature dire wolf weighed only 75-148 pounds and stood 2.5 feet at the shoulder.
The dire wolf was not in the Arctic or northern boreal forest, it was a southern animal ranging throughout most of the United States, Mexico and a few places in South America. The most northern extent of its distribution was just over the U.S. border in extreme southern Canada. There is no evidence indicating what color they were, but with this southerly distribution, it seems unlikely they were white. They may have had light-colored coats as Colossal claims the DNA indicates, but no other southern mammal is white year-round.
The evolution of dire wolves is complicated and not fully understood. The last peer-reviewed paper, published in 2021, investigated the evolutionary history and relatedness to gray wolves by analyzing DNA from dire wolf specimens that are tens of thousands of years old. The genetic information indicates dire wolves and gray wolves have very different evolutionary histories. They reported the dire wolf split off from the ancestors of gray wolves and coyotes 4 to 6 million years ago, about the time humans were starting to walk upright most of the time. Some co-authors of that paper are now working for, or collaborating with, Colossal on the dire wolf project and recently released an unpublished paper confirming this divergent evolution of dire wolves and gray wolves.
However, in interviews with media, Colossal employees were quoted as saying dire and gray wolves were very similar, sharing an estimated 99.5 percent of their DNA. Colossal is a commercial, not academic, venture so publishing scientific papers is not a priority. This is unfortunate for the scientific community, which would like to fact-check these claims, but can’t if Colossal doesn’t “show its work.” Colossal may be right about the claims quoted in the popular press, but I form my thoughts based on what I read in scientific journals, not Time magazine. Hopefully it will publish its work so we all can benefit from it.
The Dire Recipe
How did Colossal’s scientists cook up the white animals they are calling dire wolves? They extracted DNA from two of the specimens used in the earlier study: a 13,000-year-old male dire wolf from Ohio and a 72,000-year-old skull from Idaho. They compared the genetic sequences of those two dire wolves and found 20 genes that were the same for both dire wolves, but different from gray wolves. Those genes are thought to represent dire wolves so they replicated those sequences and replaced the same genes in a gray wolf genome. A few of these genes were related to physical characteristics like coat color, body size and skull growth. They then created a nucleus with that edited gray wolf genome and inserted it into a cell and implanted that in the uterus of a big domestic dog. When the puppies came to full term, they removed them by Cesarean section.
What Percent Dire Wolf Are They?
What they are not saying is what percent dire wolf these white animals are. It's a tiny percent. They identified 20 genes that were found in dire wolves and replicated parts of 14 of those in a few gray wolves. Gray wolves have about 19,000 genes. You can’t take 14 pages out of a 19,000-page book and glue them into another book and say that you’ve copied the book—even if you add a white book cover. These animals are not even close to real dire wolves, they are gray wolves with 14 genes edited.
Even if we accept the unconfirmed statements that dire wolves and gray wolves share 99.5 percent of the same DNA, that means there are roughly 95 (99.5 percent of 19,000) dire wolf genes and Colossal has edited 14. That math is as generous as you can be, but still results in these white pups being only 15 percent dire wolves. They couldn’t even replicate all 20 dire wolf-specific genes they identified because some caused blindness and deafness in gray wolves, further emphasizing that these are not functional dire wolves.
Humans and chimps share 98.8 percent of their DNA. Replicating 14 human genes in a chimp is not going to result in a human. Despite Colossal’s sensational claims, its goal is not to produce a 100 percent genetic dire wolf, but to produce a wolf that matches their vision of what a dire wolf looks like. Dog breeders have been turning wolves into various different forms for thousands of years without geneticists. I think it is more remarkable that we can turn a gray wolf into a poodle than a gray wolf into a larger white wolf. There’s no doubt you can make something that looks like a dire wolf, but that doesn’t mean you are bringing a Pleistocene animal back from extinction after being gone for 13,000 years.
Science and Pop Culture
Colossal defends its dire claims by saying it is using a morphological species concept (it looks like a dire wolf, therefore it is). There are different species concepts people argue about, but the one Colossal is using was mostly abandoned by the 1940s after being driven to extinction by the writings of Ernst Mayr and Theodosius Dobzhansky. Colossal also tries to defend its de-extinction claims by selectively quoting an international report on that topic and leaving out a lot of parts that don’t support its argument. Pay no attention to the man behind the curtain; these are not dire wolves, they are gray wolves with a few dire genes.
So why dig in and defend convoluted species definitions and sensational claims that everyone knows are not true? Have you seen “Game of Thrones”? There seems to be an obvious, and I think unhealthy, crossover between science and pop culture. We don’t know what color dire wolves were, but it is unlikely they were white. It is odd then that Colossal’s rendition of a dire wolf looks exactly like the “Game of Thrones” character Jon Snow’s dire wolf named “Ghost.” The third white wolf produced by Colossal was named “Khaleesi” after another “Game of Thrones” character. George R. R. Martin, the author of the book series the show is based on, is a “cultural advisor” and financial donor of Colossal’s dire wolf program. So, what a stroke of coincidence that Colossal’s gene editing efforts conjured up an animal that mirrored—exactly—the iconic white dire wolf that accompanies the main character. The initial release of this news to a dizzying array of media sources was accompanied by photos of Mr. Martin holding the white imposters and the pups sleeping on the famous “Iron Throne” from the movie series. This is more theater than science.
Introducing Look-Alike Species into the Wild
Even if we could make a 100 percent genetically dire wolf, what then? The narrative being peddled is that these genetically engineered animals can be “returned” to the wild to restore the ecosystem function of dire wolves and woolly mammoths. The obvious problem with those statements is that those ecosystems they used to function in have been gone for more than 10,000 years. What we have now are completely different assemblages of interacting plants and animals that have reached some relative ecosystem stability. Dumping an animal on top of these ecosystems would be an ecological disaster.
The IUCN Canid Specialist Group is the world’s chief body of scientific expertise on the status and conservation of all canid (dog) species. It distributed a press release to caution against such nonsense. It warned that editing the genome of a gray wolf to produce animals that resemble an extinct species with no remaining ecological home may threaten the conservation status of existing species.
Animals that became extinct at the end of the Pleistocene because of dramatically changing ecological conditions played the game of evolution and lost. Through no fault of their own they are, nevertheless, losers. Current talk of unleashing dire wolves on Fort Berthold Indian Reservation in North Dakota is reckless and not a solution to any existing ecological or conservation problem.
Saving Animals from Extinction
The technology, however, could be used to restore lost genetic diversity in endangered species preserved in specimens. This is not “de-extinction,” but helping to prevent extinction. That could involve editing lost genetic diversity back into the same species if that is what is needed for recovery. There are certain to be applications for this intensive genetic management, but endangered species become endangered because of other factors presenting risks to their persistence.
Colossal also claims to have cloned four endangered red wolves. That sounds fantastic, except that they are coyotes with some historical red wolf genes. Red wolf expert Dr. Joseph Hinton was the field supervisor for the Gulf Coast Canine Project in 2022 when he captured one of the coyotes (LA52F) in Louisiana that was later used by Colossal to clone another coyote that it marketed as a red wolf. The U.S. Fish and Wildlife Service uses seven measurements to determine if a canid is a red wolf and this coyote failed on six of those. This coyote also did not have enough red wolf genetics in it to meet the 87 percent threshold to qualify as a red wolf. Although the coyote donors for the cloning experiment have red wolf genes, they are not red wolves. Dr. Hinton calls this cloning effort “a solution in search of a problem” and has since left the Gulf Coast Canine Project because of its work with Colossal so he can focus on meaningful red wolf conservation efforts.
In the wild, challenges to red wolf recovery are not related to loss of genetic diversity, but to too much human-caused mortality that can result in more hybridization between red wolves and coyotes. What is needed is more human tolerance on the landscape to allow red wolves to survive and reproduce, and also more cooperating facilities to expand the captive population. Genetic manipulation might be helpful in the future of the red wolf, but cloning coyotes and calling them red wolves does not contribute to their conservation.
Trust the Science
“Trust the science” is about the most unscientific thing anyone can say. Science itself is a constant effort to disprove existing science and verify the work of others. Creating look-alike species and promoting them as dire wolves by using an outdated definition of species is not honest and it’s not good science communication. Today, distrust of science and of scientists is at an all-time high, and that will continue if people keep telling us they have brought the dire wolf back from extinction and are working to do the same for the woolly mammoth and Tasmanian tiger. For those species that have been extinct for more than 10,000 years, there is no ecological justification for their return. Conservation of endangered species has to remain focused on identifying, and managing, the things that threaten their existence. Cloned and look-alike animals from pop culture detract from, rather than contribute to, solving the real conservation issues we face.
About the Author
A wildlife biologist with degrees from the University of Wisconsin-Stevens Point and Texas A&M University-Kingsville, Jim Heffelfinger has worked for state and federal wildlife agencies and universities and in the private sector. He is the author of Deer of the Southwest and the author or co-author of more than 200 magazine articles, 50 scientific papers, 20 book chapters and numerous outdoor TV scripts. Chairman of the Western Association of Fish and Wildlife Agencies’ Mule Deer Working Group, representing 24 Western states and Canadian provinces, he also is the recipient of the Wallmo Award, presented to the leading mule deer biologist in North America, and was named the Mule Deer Foundation’s 2009 Professional of the Year. A member of the International Defensive Pistol Association and the U.S. Practical Shooting Association, Heffelfinger enjoys weekly competitions with his 1911. The opinions expressed here are his own and reflect his personal point of view.