Colossal Biosciences is celebrating a historic milestone as the world’s first de-extinct dire wolves, Romulus and Remus, turn one year old this month. The company announced the successful birth of the cloned dire wolves earlier this year, marking a significant breakthrough in de-extinction science.
The dire wolf pups represent the first living members of their species in approximately 13,000 years, since the species went extinct during the late Pleistocene era. Colossal used genetic material from a 13,000-year-old tooth discovered in Ohio’s Sheriden Cave and a 72,000-year-old ear bone from Idaho to reconstruct the ancient genome.
The groundbreaking achievement involved 20 unique precision germline edits using CRISPR technology, including 15 edits directly from ancient dire wolf gene variants. This represents a record number of precise genetic edits in any animal cloning project, surpassing the previous record of eight edits in woolly mice.
Colossal employed a novel, non-invasive cloning method using blood-derived epithelial progenitor cells from gray wolves, the closest living relatives to dire wolves. The process involved somatic cell nuclear transfer, where edited nuclei were transferred into enucleated donor egg cells and implanted into surrogate domestic dogs.
While dire wolves and gray wolves share significant genetic similarities, Colossal identified approximately twenty key genetic differences that distinguish the species, requiring the extensive editing to replicate distinctive dire wolf traits like larger body size, wider head structure, and pale coat coloration.
The company has raised over $555 million in total funding for its various de-extinction projects, including the dire wolf initiative. This includes a recent $120 million extension to their Series C round announced in September 2025.
Romulus, Remus, and their sibling Khaleesi currently reside on an 800-acre reserve designed to mimic their natural habitat, where they are monitored by veterinary staff. The company plans to maintain the animals in these controlled, secure environments rather than releasing them into the wild, ensuring their health and safety while advancing scientific understanding of de-extinction technology.