Scientists did not bring dire wolves back from extinction
Dire wolves, extinct for 10,000 years, have returned. At least that’s the claim made by biotech company Colossal Biosciences. The breakthrough is all over mainstream media and even made the front cover of Time Magazine. Have they really brought this iconic species back from the dead? Not at all. It’s not about technicalities or semantics. Dire wolves are gone. As of April 2025, we do not have the means to bring them back. But we’ve all seen the wolves in Colossal’s press materials so what exactly is going on? What is a dire wolf and what is this trio of beautiful white wolves?
Extremely distant cousins
Dire wolves (Aenocyon dirus) are an extinct mammal that looked similar to the wolves we see today but were bigger, with stronger jaws to munch on the now extinct megafauna (mammoths, giant sloths etc) that roamed what is now North America. Dire wolves lived tens of thousands of years ago, so it may be tempting to think of them as being very closely related to extant wolves and our chihuahuas. After all, Neanderthals were also around tens of thousands of years ago and extremely closely related to Homo sapiens. However, dire wolves are more distantly related than you may expect and weren’t just a larger version of the wolves we see today. Indeed, they belong in an entirely different genus (Aenocyon) than grey wolves and domesticated dogs (both in Canis).
Our taxonomy is always changing as new evidence emergences but the most recent DNA evidence puts dire wolves in a lineage splitting from the ancestors of wolves, coyotes, jackals, and African hunting dogs approximately 5.7 million years ago. Forget Neanderthals, that’s more like our separation from chimpanzees. Dire wolves and grey wolves became superficially similar due to convergent evolution but their ancestors have been on their own evolutionary journeys long enough to have brought about all the differences between ourselves and chimps. The dire wolf really was its own thing.
A Colossal achievement
When we hear an extinct species has been brought back to life, it’s difficult not to recall the scientists of Jurassic Park bringing back non-avian dinosaurs. The comparison might not be far off, especially if you’re more familiar with the novel than the movie. Crichton’s original story revealed each “dinosaur” created by the lab was actually something entirely new, or even a monster in the eyes of one character. Yes, they were uncovering real dinosaur DNA through fossilised mosquitoes. However, that merely gave them enough genetic information to more or less build them from scratch, filling the gaps with DNA from other animals. The ancient DNA told them what makes a similar animal appear more dinosaur-like. They were really good at it.
Colossal’s scientists did something similar by extracting ancient dire wolf DNA from a couple of fossils. I strongly doubt it would be enough to generate a full genome but they had enough to compare with our living canids and spot a few differences. They found tiny differences in genes we know are associated with body size, fur colour, ear shape and more. But not much more. The lab used only 20 single nucelotide polymorphisms (SNPs). If you picture a gene that affects, say body size, an SNP is the difference of a single nucleotide in that gene.
The thinking was that they could make those changes to the genome of the grey wolves and out pops a dire wolf, as if 20 or so single nucleotide changes reflects the 5.7 million years the species have been isolated. This would be like identifying 20 differences in chimp genomes compared with us, making those changes in a human embryo, and calling it a chimp. Even if the resulting human was more hairy, it wouldn’t suddenly be a chimpanzee. It’s not even like changing our genes to unlock traits that have been lost, like trying to make birds more like theropod dinosaurs (e.g. turning chicken’s teeth genes back on). We were never chimps and they were never humans. Chimps are new and humans are new. Our last common ancestor was something else. Similarly, dire wolves and grey wolves are relatively new species and their last common ancestor differed from both.
Grey wolf cells were modified using CRISPR to give them the small number of changes to those genes believed to make the wolf bigger, fluffier, and more white. The cell nucleus was transplanted into domesticated dog cells and implanted into a surrogate dog mother. What we have now is a pet dog giving birth to… something.
Congrats on your fucked up grey wolves
By making very specific changes, the now famous trio of animals do appear quite different than your average grey wolf. So is this a success? Should we call them dire wolves? Is it enough to take an animal 5.7 million years removed from dire wolves, look at the approximately 3 billion base pairs in its genome, and simply change 20 to transform it into an extinct species from a different branch on the tree of life? Absolutely not. A famously controversial early development in genetically modified food involved making tomatoes more hardy in cold environments. Scientists took the DNA that creates antifreeze proteins in pufferfish and added it to the genome of tomatoes. I would argue that what they had created was a genetically modified tomato, which had some DNA in its genome that was the same as DNA in pufferfish. Colossal’s dire wolf claims would be like saying the tomato was a pufferfish. “We’ve recreated the pufferfish”. The difference is that the tomato had a functional but invisible change made. These wolves have been changed in ways we can see and that was the whole point. Just enough changes so you’re seeing a dire wolf when you squint. A grey wolf in dire wolves' clothing.
The trio of new animals are still grey wolves despite being messed up. Not-so-grey wolves. I think it’s going too far but some could argue they represent an entirely new species. After all, their morphological differences might mean they fit into different ecological niches than regular grey wolves. But can they breed? Presumably, but we don’t know for certain. Either way, these animals will forever live in captivity and have no real place in the natural world. Even though they aren’t dire wolves, we’ve supposedly given them some of the stereotypical features of dire wolves meaning they may not fit into the exact ecological niche of regular grey wolves even if they could ethically be allowed to live in the wild and potentially breed.
Romulus, Remus, and Khaleesi (seriously) will hopefully be well cared for by Colossal and live happy lives. I’m sure we’ll see a lot of them, especially if the media continues to accept the narrative that they’re the furry equivalent of Spielberg’s velociraptors. In reality, what we have here is involuntary cosplay. These are three grey wolves (Canis lupus) genetically engineered to be bigger and fluffier, inspired by the dire wolf. That’s it. The conversation should be on the genuinely state-of-the-art science that went into their creation, or the ethical implications of bringing back extinct species, but instead science communicators have to waste time fighting Colossal’s misleading press statements and social media.