Key Points
- Colossal Biosciences says it has raised three dire wolf pups.
- It claims it modified the genome of a modern wolf using dire wolf genes.
- But scientists have claimed this "does not make a dire wolf".
US biotechnology company Colossal Biosciences claims it has produced three dire wolves, a species that has been extinct for over 10,000 years, by modifying the genome of a modern day grey wolf using dire wolf DNA found in fossils.
Colossal released footage which it said featured "dire wolf" adolescent cubs Romulus and Remus.
According to Colossal, some of the dire wolf fossils their team utilised for DNA extraction included a 13,000-year-old dire wolf tooth and a 72,000-year-old inner ear bone.
One female puppy Khaleesi was also part of the "successfully birthed" cubs, they added.
Reuters could not independently verify Colossal's claims, nor the location and the date of footage.
Corey Bradshaw, professor of global ecology at Australia’s Flinders University, was sceptical of Colossal’s claims and the actual practicality of reviving an extinct species like the dire wolf.
As Bradshaw explained, it’s practically impossible to modify the entire genomes of animals that have been extinct for thousands of years due to factors like DNA degradation.
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"So yes, they have slightly genetically modified wolves, maybe. And that's probably the best that you're going to get. And those slight modifications seem to have been derived from retrieved dire wolf material. Does that make it a dire wolf? No. Does it make a slightly modified grey wolf? Yes," Bradshaw told Reuters.
"When you claim all these great big things and then you don't provide the associated evidence, especially in something as controversial as this, that is a massive red flag," he said.
"It suggests that, well, at best, they've over-exaggerated. At worst, they're lying through their teeth".

The wolf pups are being hand-fed and closely monitored by the scientists. Source: Supplied / Colossal Biosciences
"You can use the phylogenetic [evolutionary relationships] species concept to determine what you’re going to call a species, which is what you are implying… We are using the morphological species concept and saying, if they look like this animal, then they are the animal," she said.
Emily Roycroft, of Monash University's Evolutionary and Conservation Genomics Research Group told ABC News that what makes a species is complex.
"The genetic edits may have given these wolves a lighter coat to look reminiscent of a dire wolf — but what makes a species is more than just skin deep.
"Extinct dire wolves are around 5.7 million years diverged from living grey wolves, and a lot of evolutionary and genetic changes happened across those millions of years.
"Editing a few genes of the grey wolf does not make a dire wolf," she said.
Colossal Biosciences was founded in 2021, and claims it is the first biotechnology company to use CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) gene editing technology to research species de-extinction.
Colossal also said it has recently cloned critically endangered red wolves using the same technology, as well as the hybrid Colossal Woolly Mouse —mice genetically engineered to possess traits of the long-extinct wooly-mammoth.