Two years after their birth, three dire wolves engineered by Colossal Laboratories & Biosciences have reached full physical maturity, according to a report from the biotech firm. The animals, born to surrogate dog mothers, are now being monitored by researchers to evaluate the success of the genetic modifications used to recreate the prehistoric predator, which went extinct approximately 13,000 years ago.
Dire Wolves Reach Full Size
The first two males, Romulus and Remus, were born on October 1, 2024. As of their second birthday in October 2026, both have reached adulthood and are in good health. Romulus, the larger of the two, weighs 134 pounds, while Remus weighs 132 pounds. Both measure nearly seven feet from nose to tail. Their younger sister, Khaleesi, who was born four months after her brothers, weighed 102 pounds during her most recent health assessment.
Researchers at Colossal Biosciences edited the gray wolf genome to express traits characteristic of the extinct dire wolf. According to Beth Shapiro, the company’s chief science officer, the physical development of the male wolves aligns with the expected metrics derived from the fossil record, marking a success in the genetic editing process. While their weights are comparable to those of average gray wolves, the engineered animals exhibit distinct physical differences, including wider faces and more powerful musculature.
Pack Forms on Preserve
The three wolves, which reside on a 2,000-acre preserve, have established a stable social unit. Khaleesi joined her brothers in August 2025, and the group has since functioned as a pack, with Remus identified as the leader.
The project follows earlier, less successful attempts at de-extinction, such as the 2009 effort to revive the Pyrenean ibex and the 2003 cloning of a banteng, both of which faced significant health complications. Colossal Biosciences, which previously announced plans to resurrect the woolly mammoth and the dodo bird, stated that the study of these dire wolves provides critical insights into the importance of biodiversity and the restoration of lost habitats.