In a stunning scientific achievement that reads like science fiction come to life, Colossal Biosciences has successfully brought back dire wolves—iconic Ice Age predators that vanished approximately 12,000 years ago. On April 8, 2025, the Dallas-based biotechnology company announced the birth of three healthy dire wolf pups, marking the world’s first successful de-extinction of an animal species.
The Dire Wolf Returns
Dire wolves (Aenocyon dirus), once known only from fossils and pop culture references like Game of Thrones, are now walking the earth again. The announcement revealed the birth of three pups named Romulus and Remus (males born in October 2024) and Khaleesi (a female born in January 2025).
“These are not dogs, or even modern-day wolves. They’re dire wolf pups, back from extinction after some 12,000 years,” notes Colossal’s documentation of the achievement. The pups already exhibit classic dire wolf traits, including thick white fur, broad heads, and hefty builds. At just six months old, the male pups weigh approximately 80 pounds.
Unlike domestic puppies, these animals display true wild instincts, keeping their distance from humans and showing caution even around familiar caretakers. They’re currently housed on a secure 2,000+ acre ecological preserve that’s certified by the American Humane Society and registered with the USDA.
Groundbreaking Science Behind the Revival
The resurrection of dire wolves represents a fusion of cutting-edge genomic technologies. Rather than directly cloning a frozen specimen (none exist), Colossal reconstructed the dire wolf through multiple sophisticated steps:
- Ancient DNA Recovery: Scientists extracted genetic material from a 13,000-year-old dire wolf tooth and a 72,000-year-old skull.
- Genome Reconstruction: From these fragments, researchers sequenced and assembled the dire wolf’s genome, creating a genetic blueprint of the extinct species.
- Key Trait Identification: Scientists identified 14 important genes (with 20 distinct genetic variants) that give dire wolves their characteristic features, including size, coat, and skull structure.
- CRISPR Gene Editing: Colossal edited living cells from gray wolves (the dire wolf’s closest living relative) to carry dire wolf genes, precisely rewriting the DNA to install the 20 dire wolf variants.
- Cloning: Using somatic cell nuclear transfer, scientists placed the edited cell nuclei into egg cells, creating viable embryos.
- Surrogate Birth: These embryos were implanted into surrogate mothers—domestic dogs—resulting in the successful birth of the three pups via cesarean section.
“This massive milestone is the first of many coming examples demonstrating that our end-to-end de-extinction technology stack works,” said Ben Lamm, CEO of Colossal. “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 achievement set a scientific record, with 20 precise genetic edits being made to create the dire wolves—the highest number of deliberate genome edits in any animal to date.
Conservation Applications
Beyond the headline-grabbing resurrection of dire wolves, Colossal emphasizes that this technology has immediate applications for endangered species conservation. Alongside the dire wolf births, the company announced it had successfully cloned two litters of critically endangered red wolves (Canis rufus), producing four healthy pups using the same “non-invasive blood cloning” approach developed in the dire wolf work.
With fewer than 20 red wolves remaining in North America, this achievement could significantly impact conservation efforts for the world’s most endangered wolf species.
Dr. Christopher Mason, a Colossal scientific advisor, highlighted the broader implications: “The same technologies that created the dire wolf can directly help save a variety of other endangered animals as well. This is an extraordinary technological leap in genetic engineering efforts for both science and conservation.”
Looking Forward
Colossal’s success with dire wolves validates its de-extinction platform and boosts confidence that more ambitious targets, like the woolly mammoth (targeted for 2028), are within reach. As Robin Ganzert, Ph.D., CEO of the American Humane Society, notes: “The technology they are pursuing may be the key to reversing the sixth mass extinction and making extinction events a thing of the past.”
For Colossal, founded in 2021 with the bold tagline of making “extinction optional,” this achievement delivers on a promise to do what has never been done before. It opens new possibilities not just for bringing back lost species, but for saving those on the brink of extinction today.
As George R.R. Martin, Game of Thrones creator and Colossal investor, aptly put it: “I get the luxury to write about magic, but Ben and Colossal have created magic by bringing these majestic beasts back to our world.”
