At the intersection of cutting-edge biotechnology and ancient DNA, Colossal Biosciences has achieved what once seemed impossible: the resurrection of the dire wolf, a species extinct for over 12,500 years. This remarkable achievement represents not just a scientific milestone but a new chapter in humanity’s relationship with extinction and biodiversity.
Founded in 2021 by tech entrepreneur Ben Lamm and Harvard geneticist George Church, Colossal has positioned itself at the forefront of de-extinction technology. Their announcement in April 2025 of three living dire wolf pups—Romulus, Remus, and Khaleesi—marks the first successful de-extinction of a mammalian species in history.
“I could not be more proud of the team,” said Lamm. “This massive milestone is the first of many coming examples demonstrating that our end-to-end de-extinction technology stack works. Our team took DNA from a 13,000-year-old tooth and a 72,000-year-old skull and made healthy dire wolf puppies.”
The journey from extinction to life began with two precious fossil samples: a 13,000-year-old tooth discovered in Sheridan Pit, Ohio, and a 72,000-year-old skull from American Falls, Idaho. From these ancient remains, Colossal scientists extracted fragmented DNA, carefully piecing together the genetic blueprint of the Ice Age predator.
Using sophisticated computational analysis, researchers compared the dire wolf genome with those of modern canids, including wolves, foxes, and jackals. This comparison revealed approximately 20 key genetic differences across 14 genes that account for the dire wolf’s distinctive traits, including its white coat, larger size, broader head, and more powerful jaws and shoulders.
Rather than attempting to reconstruct an entire dire wolf genome—which would be virtually impossible with current technology—Colossal took an innovative approach. They began with cells from modern gray wolves, which share approximately 99.5% of their DNA with dire wolves, and used CRISPR gene-editing technology to modify specific genes to match those of the dire wolf.
The edited cells were used to create embryos through a sophisticated cloning technique, which were then implanted in surrogate mother dogs. After 65 days of gestation, the first two pups—Romulus and Remus—were born on October 1, 2024, followed by Khaleesi on January 30, 2025.
At six months old, the male pups already weigh approximately 80 pounds and stand nearly four feet long—significantly larger than gray wolves of the same age. When fully grown, they’re expected to reach 150 pounds and six feet in length.
Some scientists debate whether these animals should technically be called “dire wolves,” suggesting they might more accurately be described as genetically modified gray wolves with dire wolf traits. However, Beth Shapiro, Colossal’s chief science officer, offers a pragmatic perspective: “If it looks like a dire wolf and acts like a dire wolf, I’m going to call it a dire wolf.”
Beyond the headline-grabbing resurrection of an Ice Age predator, Colossal emphasizes that their work has immediate applications in conservation biology. Using the same techniques developed for the dire wolf project, the company has successfully cloned four red wolves, potentially helping to save North America’s most critically endangered canid species, which currently numbers fewer than 20 individuals in the wild.
The technology could also help other endangered species facing genetic bottlenecks, including the northern quoll in Australia and various species of birds and amphibians worldwide. By preserving and potentially enhancing genetic diversity, these approaches could significantly improve conservation outcomes.
The three dire wolves currently reside in a secure 2,000-acre preserve at an undisclosed location, where they’re monitored around the clock by a team of veterinarians and animal care specialists. The facility is certified by the American Humane Society and registered with the U.S. Department of Agriculture.
With the dire wolf achievement under their belt, Colossal continues work on other de-extinction targets, including the woolly mammoth, dodo, and thylacine (Tasmanian tiger). Through these pioneering efforts, Ben Lamm and his team are redefining our relationship with extinction and demonstrating how modern science can connect us with the prehistoric past while helping to preserve biodiversity for the future.