Life › Life & humans today › CRISPR gene editing
De-extinction & the 2025 'dire wolf' claim
April 2025 (Colossal Biosciences); disputed· Event· Animals
DebatedScientists disagree about when, how or why.
Efforts to recreate lost species by cloning or gene editing; in 2025 a company announced three 'dire wolves', a claim many scientists reject.
See it on the Life map →What happened
In April 2025 Colossal Biosciences, a Texas company, announced three pups: Romulus, Remus and Khaleesi. It had made 20 edits in 14 genes of gray wolf cells, guided by DNA from dire wolf fossils 13,000 and 72,000 years old, then cloned the cells using dog surrogate mothers. Dire wolves died out about 13,000 years ago and split from gray wolves' ancestors millions of years earlier. The first de-extinction, a cloned Pyrenean ibex in 2003, lived only minutes.
Why it matters
It tests whether gene technology can reverse extinction, and raises hard questions about what defines a species and how conservation money is best spent.
Think of it like
Like renovating a building to look like a demolished landmark: the facade matches, but most of the structure is new.
The evidence (fossils, genes, rocks)
Colossal's announcement and a preprint, not peer-reviewed at launch. The IUCN's wolf and dog specialist group said the pups are not dire wolves; Colossal's chief scientist called them gray wolves with 20 edits.
Still debated
Whether an edited animal can ever count as the lost species, whether it could live in the wild, and whether the effort diverts resources from saving living species.
Connections (4)
▸Woolly mammoth is a target of De-extinction & the 2025 'dire wolf' claimStrong evidence
The connection
The mammoth is the flagship target of de-extinction. Colossal Biosciences plans to edit cells of the Asian elephant, the mammoth's closest living relative, with mammoth versions of genes for hair, fat and cold tolerance. In March 2025 it showed 'woolly mice' with long, thick coats from similar edits. It aims for calves by 2028.
When and how
Colossal, founded in 2021 in Dallas by entrepreneur Ben Lamm and geneticist George Church, whose Harvard lab began mammoth gene work in the 2010s.
How sure are we?
Mammoth genomes read from permafrost remains since 2008 make the edits possible; Colossal's progress claims are company announcements, mostly not yet peer-reviewed.
Debates and open questions
Whether a hairy edited elephant counts as a mammoth, the ethics of using endangered elephants as surrogates, and whether herds could help Arctic ecosystems.
▸Dodo extinction is a target of De-extinction & the 2025 'dire wolf' claimStrong evidence
The connection
The dodo, a flightless pigeon wiped out on Mauritius by the late 1600s, is a symbol of human-caused extinction and a de-extinction target. Birds cannot be cloned like mammals, so Colossal plans to edit cells of the Nicobar pigeon, the dodo's closest living relative, and grow them into germ cells carried by surrogate birds.
When and how
Colossal announced its dodo project in January 2023 with paleogeneticist Beth Shapiro, whose team had sequenced the dodo genome; partners include the Mauritian Wildlife Foundation.
How sure are we?
The dodo genome, read from a museum specimen, makes the attempt technically conceivable; progress so far is company-reported, and no bird exists yet.
Debates and open questions
Whether the result would be a dodo or an edited pigeon, and whether Mauritius, still overrun by rats and introduced monkeys, could support it.
▸A sixth mass extinction? spurs attempts at De-extinction & the 2025 'dire wolf' claimWell established
The connection
Accelerating species losses motivate de-extinction groups, which pitch their tools as conservation aids too. Revive & Restore helped clone a black-footed ferret from cells frozen in 1988, adding genetic diversity to an endangered species. Colossal likewise says its methods can help threatened animals, not only lost ones.
When and how
Revive & Restore, founded 2012 by Stewart Brand and Ryan Phelan; Colossal, 2021; the cloned ferret Elizabeth Ann was born in Colorado in December 2020.
The evidence
The groups state this rationale openly, and the ferret clone and a cloned Przewalski's horse (2020) are real conservation results.
Debates and open questions
Critics warn it may divert funding from protecting habitat, or make extinction seem reversible and therefore less urgent.
▸CRISPR gene editing was used in De-extinction & the 2025 'dire wolf' claimWell established
The connection
Colossal used CRISPR to make 20 edits in 14 genes of gray wolf cells, choosing dire wolf traits such as larger size and a thick, pale coat. The edited cells were cloned into dog eggs, and the embryos carried by dog surrogates. For some traits it used variants known from living canids rather than the exact dire wolf versions.
When and how
Colossal Biosciences, Texas; pups born in October 2024 and January 2025, announced in April 2025.
The evidence
The company released a preprint describing the edits and the ancient genomes; outside geneticists note that dire and gray wolves differ at millions of DNA sites, not 20.
Debates and open questions
Which, if any, of the edits capture what made dire wolves distinct, and how the pups' long-term health and behavior will turn out.