Have Dire Wolves, Which Went Extinct More Than 10,000 Years Ago, Really Been Brought Back to Life? Pioneers in the science of “de-extinction,” an American company has announced the births of three pups whose genes resemble those of a species that hasn’t roamed Earth for millennia Romulus and Remus, pups that the company Colossal Biosciences says are the first dire wolves to roam the planet in several thousand years, are seen at one month old. Colossal Biosciences A researcher holds two snow-white wolf pups as they howl at the top of their adorable little lungs. Their names are Romulus and Remus—in honor of the siblings associated with the mythical founding of ancient Rome—but they’re not any kind of wolf you’ve ever seen. They’re dire wolves… ish. Made popular as the giant pets owned by the Stark children in Game of Thrones, the canine species went extinct more than 10,000 years ago.On Monday, the biotechnology startup Colossal Biosciences—known as the “de-extinction” company—announced the birth of Romulus, Remus and a third dire wolf, a female named Khaleesi (in reference to the Game of Thrones character Daenerys Targaryen). According to the firm’s statement, the dire wolf has just become “the world’s first successfully de-extincted animal.” Given the pups’ genetic similarity to gray wolves, however, some scientists are challenging this claim. Dire wolves roamed the Earth during the Pleistocene, between around 11,700 and 2.6 million years ago. Paleontologists have consistently unearthed their remains in North and South America, and they’re the most common mammal to appear in the La Brea Tar Pits of California. Compared to the modern gray wolf, the species’ closest living relative, dire wolves were larger and had bigger teeth. Since it formed in 2021, Colossal Biosciences has been known for its highly publicized efforts to “resurrect” extinct woolly mammoths, dodos and Tasmanian tigers. But their work with dire wolves had not previously been announced, writes CNN’s Katie Hunt. The First Dire Wolf Howl in Over 10,000 Years Watch on The company plans to “bring back” these species by editing the genomes of their living relatives, creating a creature that closely approximates their target. To birth Romulus, Remus and Khaleesi, researchers at Colossal extracted, sequenced and analyzed the dire wolf genome from a 13,000-year-old dire wolf tooth and a 72,000-year-old dire wolf skull. “Getting the genome was really hard, they didn’t live in cold climates, so the DNA wasn’t as well preserved,” Beth Shapiro, Colossal’s chief science officer and a researcher at the University of California at Santa Cruz, tells Bloomberg’s Josh Saul. They then compared it to the genome of a gray wolf, among other living canids. The comparison revealed 20 differences in 14 genes linked to distinct dire wolf traits, including a larger size, wider head, bigger teeth and white fur. The researchers edited gray wolf genes to match those characteristics, then inserted them into the egg cells of a domesticated dog, with the cells’ own DNA removed. The eggs developed into embryos, which were then transplanted into the wombs of large hound mixes, resulting in the births of Romulus and Remus in October, and Khaleesi in January, all via cesarean section. Another female dire wolf was born in January, but she died ten days later from an intestinal infection that Colossal says was not related to the genetic edits. Now, the modern-day dire wolves reside in a fenced-in ecological preserve certified by the American Humane Society in an undisclosed area of the northern United States. They are essentially “living the Ritz Carlton lifestyle of a wolf,” Shapiro tells the New York Times’ Carl Zimmer. Thanks to cameras and drones, “they can’t get a splinter without us knowing about it.” Dire wolf DNA is 99.5 percent identical to that of gray wolves, Shapiro tells New Scientist’s Michael Le Page. But that 0.5 percent difference could consist of millions of base pairs. This raises the question of whether the pups are really dire wolves or just genetically modified gray wolves. Scientists not connected to the initiative point out that dire wolves might have countless other genetic differences that were not accounted for in the 20 changes made by Colossal’s team. “We have a mostly gray wolf that looks like a dire wolf,” Julie Meachen, a vertebrate paleontologist from Des Moines University who was not involved in the project, says to ABC News. Meachen co-authored a paper on the evolution of dire wolves along with Shapiro in 2021, which found that the species is genetically distinct from gray wolves, having diverged from the wolf lineage nearly six million years ago. As for these new creatures, Meachen adds, “I don’t think they are actually dire wolves.” Shapiro tells Wired’s Emily Mullin and Matt Reynolds that “if we can look at this animal and see what it’s doing, and it looks like a dire wolf and acts like a dire wolf, I’m going to call it a dire wolf. And my colleagues who are taxonomists will disagree with me.” Romulus and Remus, pictured at three months old, can run around outside in their enclosure at an undisclosed location. Colossal Biosciences Other scientists point out that the pups might not know how to act like dire wolves. Romulus, Remus and Khaleesi are unlikely to exhibit behaviors typical of wild dire wolves due to being raised in captivity without a pack structure, says Adam Boyko, a geneticist at Cornell University who was not involved in the project, to the New York Times. He adds that since the dire wolves are not consuming the ancient dire wolf diet, they are also not developing their ancestors’ intestinal microbes. Nevertheless, Colossal CEO Ben Lam maintains that “if we are successful in de-extinction, we’re building technologies that can help human health care and conservation,” as he tells Bloomberg. In this spirit, Colossal also birthed two litters of cloned red wolves—the most endangered wolf species in the world. Just last month, the company announced the birth of “woolly mice”, which they say is a critical step in the de-extinction of woolly mammoths. In October last year, they also claimed to have built the most complete ancient genome to date, belonging to the Tasmanian tiger. But some have raised questions about what the conservation purpose of these dire wolves will be, or how “de-extinct” species could be released into the wild ecosystems of today. “In states like Montana, we are currently having trouble keeping a healthy population of gray wolves on the land in the face of amped up political opposition,” Christopher Preston, an environmental philosopher at the University of Montana, tells CNN. “It is hard to imagine dire wolves ever being released and taking up an ecological role. So, I think it is important to ask what role the new animals will serve.” Get the latest stories in your inbox every weekday.