Just like Game of Thrones – but real: First dire wolves born in over 10,000 years
Many people know direwolves only from the fantasy world of Game of Thrones, but the real creatures (Aenocyon dirus) once roamed North and South America before the last ice age. These now-extinct dire wolves were much larger and sturdier than modern wolves, standing up to 35 inches at the shoulder and weighing up to 240 pounds. In contrast, today’s gray wolves typically weigh between 88 and 110 pounds and stand 24 to 31 inches tall at the shoulder.
On October 1, 2024, a dire wolf’s howl echoed through a Texas laboratory for the first time in over 10,000 years. This historic moment was made possible by Colossal Biosciences, a U.S. company focused on de-extinction – reviving species that have long vanished from the Earth. The birth of two pups, named Romulus and Remus, marked a major breakthrough. They are the first successfully brought-back members of an extinct species. A third pup, fittingly named Khaleesi after the Game of Thrones dragon queen, was born on January 30, 2025. The announcement came with a post on X, featuring the pups' first recorded howls.
CRISPR and fossil DNA: how a direwolf is created
The foundation of this groundbreaking project was a fully reconstructed DNA sequence, based on fossilized remains estimated to be between 11,500 and 72,000 years old. Using advanced CRISPR technology, which allows for the precise modification of genetic material, scientists edited 14 genes at 20 specific locations to replicate the genome of the extinct dire wolf as closely as possible. The edited embryos were implanted into surrogate mothers, specifically selected mixed-breed dogs. The outcome has been impressive. The pups already weigh around 80 pounds and measure up to 4 feet in length, closely resembling their prehistoric ancestors.
Colossal sees itself as a pioneer in the field of de-extinction. The company aims to make history, restore damaged ecosystems and counteract species loss through cutting-edge biotechnology. Alongside the dire wolf, Colossal is also working on bringing back the woolly mammoth and the Tasmanian tiger. The company outlines its vision for a better, more biodiverse planet in a video on YouTube, showcasing its mission and the science behind these ambitious projects:
Criticism from scientists: No real Dire Wolves
Leading paleogeneticists such as Nic Rawlence from the Otago Palaeogenetics Laboratory and Vincent Lynch from the University at Buffalo remain critical of the project. Rawlence explains that these animals are not true dire wolves but genetically modified gray wolves, as the fossil DNA is too fragmented to allow complete cloning. Lynch also emphasizes that having a sequenced genome alone is not enough to fully bring back an extinct species. The animals may appear similar to their ancient counterparts in size, build and fur color, but genetically they do not represent a true recreation of the original species. This raises an important question for science and ethics alike – where does resurrection end and re-creation begin?
The revival of dire wolves has also sparked a debate on Reddit, where many users express skepticism about the project's true motives. Critics argue that the initiative seems less focused on biodiversity and more aimed at attracting investor interest. Some even compare it to breeding exotic pets, warning that de-extinction could become increasingly commercialized under the pretense of conservation.
Source(s)
Colossal Biosciences via X (formerly Twitter)
Image source: YouTube / Colossal Biosciences
