1.Their names are Romulus, Remus and Khaleesi, and they’re the first dire wolves to walk the Earth in over 10,000 years — or so one biotech company and a flurry of recent headlines say. On April 7, Colossal Biosciences announced what they called the “world’s first de-extinction,” the births of three dire wolves, extinct animals that lived during the ice ages of the Pleistocene. The pups were instant icons. With snowy-white coats and muscular bodies.
2.News reports heralded the animals as “scientifically seismic” and said “the dire wolf is back.” Still, some scientists aren’t buying it. “That is no more a dire wolf than I am Wonder Woman,” says Jacquelyn Gill, a paleoecologist at the University of Maine in Orono. The issue largely boils down to genetics. Colossal didn’t create the animals from a fully reconstructed dire wolf genome.
3.Instead, the company relied on the genetic instruction book of a gray wolf, making changes to it based on ancient DNA recovered from two dire wolf specimens. But, Gill says, “for something to be a dire wolf, it should have the full genetic blueprint of a dire wolf.” What Colossal has done, she says, is simply create a genetically modified gray wolf. But that type of thinking “kind of misses the point,” says Beth Shapiro, chief science officer at Colossal Biosciences in Dallas.
4.Colossal’s goal wasn’t to create something genetically identical to a dire wolf, she says. Instead, researchers wanted to resurrect the animal’s core attributes, like size, body type and face shape. By making a handful of genetic changes, “we’ve brought these extinct genes back to life in a living animal,” she says. Ultimately, Shapiro says, “I’m happy to call that a dire wolf.”And a new preprint to be posted soon counters one common critique of the work, showing that dire wolves may be more closely related to modern wolves than previously thought.
5. Colossal is no stranger to controversy. Last month, the company garnered acclaim with its announcement of “woolly mice,” luxuriously tressed mice with genetic modifications inspired by woolly mammoths. The rodents’ golden-brown fluff made them internet stars, but some scientists were skeptical that such a creation brought the field any closer to bringing back woolly mammoths.
6. “At the moment, I think they’re creating interesting zoo-like novelties,” says Paul Wilson, a wildlife geneticist at Trent University Ontario in Peterborough. Even so, he finds the company’s technology impressive. It goes beyond crafting a dire wolf, he says.
7.Long before Romulus, Remus and Khaleesi made their debut, dire wolves (Aenocyon dirus) roamed the Americas during the Pleistocene Epoch, which stretched from roughly 2.5 million years ago to about 12,000 years ago. Ancient DNA from two of these animals ended up informing the new pups’ biology. Colossal scientists extracted DNA from a 13,000-year-old fossilized tooth from Ohio and a 72,000-year-old inner ear bone fossil from Idaho.
8. A 2021 study using ancient DNA revealed that dire wolves are genetically distinct and diverged from other canines nearly 5.7 million years ago. Because of this deep evolutionary divide, experts say dire wolves were more like large, wolf-like cousins than ancestors to today’s gray wolves. They may have had different behaviors, ecologies, and social dynamics that can’t be recreated through minor DNA edits.
What are some possible risks of introducing genetically engineered animals into modern ecosystems? – Can you think of any past examples where human intervention in nature had unexpected results?
9.Colossal’s broader mission includes reviving other extinct species, like the woolly mammoth and dodo. Their goal is to use synthetic biology and gene editing to restore ecological functions lost when those species vanished. The company also emphasizes potential benefits for conservation. By applying gene-editing tools, they hope to boost genetic diversity in endangered species or reintroduce lost traits that could improve resilience to modern threats like climate change.
10.Yet many conservation biologists remain skeptical. They argue that efforts like this risk distracting from more urgent and practical conservation work, such as protecting habitats and addressing current threats to biodiversity. Some scientists also worry about unintended consequences. Introducing hybrid animals into ecosystems could disrupt existing balances or fail to replicate the role of the original species, which evolved over millennia in complex interactions.
11.There are also ethical and philosophical questions. What does it mean to “bring back” a species? Can a few engineered animals with similar looks truly replace a species that had its own behaviors, social structures, and evolutionary history? Despite the controversy, Colossal’s project is a major step in biotechnology. It highlights how far gene editing has come and opens new debates about how these tools should be used — and where we draw the line between innovation and imitation.
