In a move straight out of science fiction, Colossal Biosciences — a US-based biotech company — claims to have taken a giant leap toward de-extinction by creating what it calls “functional replicas” of the dire wolf. These genetically engineered wolf pups, named Romulus, Remus, and Khaleesi, have reignited both excitement and ethical debate around the science of bringing extinct species back to life.
What Is a Dire Wolf?
Made popular by the fantasy series “Game of Thrones,” the dire wolf (Aenocyon dirus) was a real animal that roamed North America during the Ice Age. These apex predators were significantly larger than today’s gray wolves — growing up to 3.5 feet tall, over 6 feet in length, and weighing as much as 68 kilograms.
Dire wolves preyed on large herbivores such as bison, horses, and even mammoths. Their extinction around 13,000 years ago is believed to have been caused by a combination of climate change and the disappearance of their prey, likely hastened by human activities.
The De-Extinction Effort by Colossal Biosciences
Colossal Biosciences was co-founded by entrepreneur Ben Lamm and world-renowned geneticist George Church. The company made headlines when it announced the birth of three genetically engineered wolf pups designed to mimic the traits of dire wolves. Romulus and Remus were born in October 2024, followed by Khaleesi in January 2025.
The process involved retrieving ancient DNA from dire wolf remains — including a 13,000-year-old tooth and a 72,000-year-old ear bone. From this data, Colossal scientists identified 20 specific genetic edits across 14 genes. These genes are believed to be responsible for the dire wolf’s distinct traits, such as its large body size, white coat, and muscular build.
By editing these genes into the genome of a modern gray wolf and implanting the modified embryos into domestic dog surrogates, Colossal successfully birthed the pups that, according to them, are modern proxies for the extinct species.
Are These Really Dire Wolves?
Many scientists are skeptical about Colossal’s claim. Experts argue that while the modified animals may look like dire wolves on the outside, they are not genetically or behaviorally identical to the real thing.
Paleogeneticist Nic Rawlence noted that dire wolves and gray wolves diverged from a common ancestor between 2.5 and 6 million years ago. This long evolutionary separation has led to profound genetic differences between the two species. Simply editing a few genes does not recreate a dire wolf — it creates something new.
Jeremy Austin, director of the Australian Centre for Ancient DNA, echoed this sentiment, pointing out that there are likely hundreds of thousands of genetic differences that cannot be accounted for by editing just 14 genes. According to him, the genetically engineered animals are not dire wolves by any scientific definition.
The Ethical and Ecological Debate
While the technological feat is impressive, it raises important questions about the purpose and impact of de-extinction efforts.
One major concern is ecological relevance. The ecosystems where dire wolves once thrived have changed drastically. It’s unclear how these engineered animals would fit into today’s habitats or what unintended consequences could emerge if they were ever introduced into the wild.
There are also ethical concerns about diverting funding and attention away from conservation efforts aimed at protecting endangered species that are still alive today. Critics argue that resources might be better spent preserving existing biodiversity rather than attempting to recreate what has already been lost.
What Does the Future Hold?
Colossal Biosciences’ project is undeniably a milestone in genetic engineering and synthetic biology. The idea of reviving extinct species has fascinated scientists and the public alike, and this development shows that science is inching closer to turning that dream into reality.
However, this project also highlights the scientific, ethical, and environmental complexities of de-extinction. Whether this leads to a new era of ecological restoration or a controversial path of “playing god” remains to be seen.
As technology advances, the world must consider not just whether we can bring back extinct species — but whether we should.
