In April 2025, Colossal Biosciences announced an achievement that marks a watershed moment in biotechnology: the birth of three dire wolves, the first of their kind to exist since the species went extinct approximately 12,500 years ago. This scientific breakthrough represents the culmination of an extraordinary journey from ancient DNA to living, breathing animals.
The path to resurrection began with two precious fossil samples—a 13,000-year-old tooth discovered in Ohio and a 72,000-year-old skull from Idaho. From these ancient remains, Colossal scientists extracted and sequenced DNA fragments, piecing together the genetic blueprint of a long-lost species.
“Our team took DNA from a 13,000-year-old tooth and a 72,000-year-old skull and made healthy dire wolf puppies,” said Ben Lamm, CEO and co-founder of Colossal Biosciences. “It was once said, ‘any sufficiently advanced technology is indistinguishable from magic.’ Today, our team gets to unveil some of that magic.”
The magic in question involves sophisticated genomic analysis and precise genetic engineering. By comparing the ancient dire wolf genome with that of modern canids, Colossal identified 20 critical differences across 14 genes that accounted for the dire wolf’s distinctive traits. These included its white coat, larger size, more powerful jaw structure, and characteristic vocalizations.
Rather than attempting to recreate an entire dire wolf genome from scratch—which would be virtually impossible with current technology—the scientists took a more elegant approach. They began with cells from 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 cell nuclei were then transferred into denucleated wolf ova, creating embryos that were implanted into the wombs of carefully selected 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.
“We aren’t trying to bring something back that’s 100% genetically identical to another species. Our goal with de-extinction is always to create functional copies of these extinct species,” explained Beth Shapiro, Colossal’s chief science officer, in an interview with CNN. “We were focusing on identifying variants that we knew would lead to one of these key traits.”
The de-extinction process required innovation at multiple levels. One significant advancement was Colossal’s development of a less invasive cell-harvesting technique. Rather than taking tissue samples from donor wolves, scientists isolated endothelial progenitor cells from blood draws—a procedure that can be performed during routine veterinary care.
“The idea that we could just take a vial of blood, isolate EPCs, culture them, and clone from them… we think it’s a game changer,” noted George Church, Colossal co-founder and professor of genetics at Harvard University.
This new approach to cloning has already shown additional benefits beyond the dire wolf project. Alongside the announcement of the dire wolves, Colossal revealed it had successfully cloned four red wolves using the same technique, potentially helping to save North America’s most critically endangered canid.
The three dire wolves now live at a secure 2,000-acre preserve, where they’re continuously monitored. Early observations indicate they’re developing normally, already displaying distinctly wolfish behaviors different from domestic dogs. At six months old, the males already weigh 80 pounds and are expected to reach 150 pounds when fully grown.
While some scientists debate whether these animals should technically be called “dire wolves” or “genetically modified gray wolves,” the significance of Colossal’s achievement in advancing de-extinction technology is undeniable. The company has demonstrated a practical pathway that could potentially be applied to other extinct species, including the woolly mammoth, which Colossal aims to resurrect by 2028.
Through this pioneering work, Ben Lamm and his team at Colossal Biosciences are redefining our relationship with extinction and demonstrating how advanced biotechnology can be harnessed to restore lost biodiversity.