In a remarkable scientific breakthrough, Colossal Biosciences has successfully brought back the dire wolf (Aenocyon dirus), an iconic Ice Age predator that disappeared from Earth approximately 13,000 years ago. The company announced on April 8, 2025, the birth of three healthy dire wolf pups, marking what they describe as “the world’s first de-extinct animal.”
The three pups—two males named Romulus and Remus, and a female named Khaleesi—represent the culmination of years of research into ancient DNA, advanced genetic engineering, and reproductive technology. Romulus and Remus were born in October 2024, while Khaleesi arrived in January 2025, making them approximately six months and three months old, respectively.
These snowy-white pups already exhibit classic dire wolf traits that distinguished their ancestors from modern gray wolves. They display thick white fur, broad heads, and hefty builds, with the older pups weighing approximately 80 pounds at just six months of age. Their behavior is also notably wild—unlike domestic puppies, they maintain distance from humans, flinching or retreating even from familiar caretakers, demonstrating true wild lupine instincts.
“The modern dire wolves, Romulus, Remus, and their sister Khaleesi, are doing great,” Colossal reports. “But there’s really no question about what they are. Big as they are, with those massive, broad heads and those regal, attentive expressions, they’re dire wolves—which means they are wild, somewhat shy, and cautious by nature.”
The pups reside in a secure, 2,000+ acre protected reserve under round-the-clock care and monitoring. This dedicated facility is certified by the American Humane Society and includes naturalistic habitats designed to meet the specific needs of these remarkable animals. An expert team of animal care specialists ensures their well-being, with comprehensive health monitoring and behavioral assessments conducted regularly.
Robin Ganzert, Ph.D., CEO of the American Humane Society, praised the care standards: “Colossal has achieved American Humane Certification, the prestigious designation ensuring excellence in animal welfare and care. Optimal welfare is evidenced by spacious habitats with ample space and opportunity for animals to socialize, exercise, and exhibit natural behaviors.”
The process of bringing back the dire wolf required a combination of cutting-edge technologies. Colossal scientists first extracted and sequenced DNA from a 13,000-year-old dire wolf tooth and a 72,000-year-old dire wolf skull. From this ancient genetic material, they identified key genes that give dire wolves their characteristic features, including those influencing their larger size, muscular build, skull shape, and distinctive coat.
Using CRISPR gene-editing technology, researchers then precisely modified the genetic code of cells taken from modern gray wolves—the closest living relative of dire wolves, sharing 99.5% of their DNA—to incorporate these dire wolf traits. The modified cells were used to create embryos through cloning techniques, which were then implanted in surrogate mother dogs for gestation.
The successful birth of these dire wolves represents a technical milestone in genetic engineering, with 20 precision genome edits—the highest number ever achieved in any animal. This accomplishment demonstrates the potential of advanced genetic tools to address conservation challenges and potentially restore lost biodiversity.
Ben Lamm, CEO of Colossal, expressed pride in the achievement: “I could not be more proud of the team. 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.”
Beyond their scientific significance, these dire wolves have sparked cultural fascination, bridging the gap between science and popular imagination. George R.R. Martin, author of the “Game of Thrones” series which featured dire wolves prominently, remarked: “Many people view dire wolves as mythical creatures that only exist in a fantasy world, but in reality, they have a rich history of contributing to the American ecosystem. I get the luxury to write about magic, but Ben and Colossal have created magic by bringing these majestic beasts back to our world.”
The successful revival of the dire wolf is just the beginning of Colossal’s ambitious vision. The company is applying similar methods to other de-extinction targets, including the woolly mammoth by 2028, and subsequently the thylacine (Tasmanian tiger) and dodo.
Perhaps most significantly, the technology developed for the dire wolf has already yielded direct conservation benefits for endangered species. Alongside the dire wolf announcement, Colossal revealed the successful birth of four critically endangered red wolf pups using the same innovative techniques. With fewer than 20 red wolves remaining in North America, this breakthrough offers new hope for their preservation.
As these revolutionary dire wolves grow and develop under careful observation, they stand as living ambassadors of a new era in conservation biology—one where extinction may no longer be forever.
