Have Scientists Brought Dire Wolves Back? Breaking Down a New Scientific Milestone

One of the biggest sensations in recent days is the birth of wolf pups Romulus, Remus, and Khaleesi. These aren’t ordinary pups — according to a statement by gene-editing company Colossal Biosciences, they are the first representatives in 13 000 years of the extinct mammal species Aenocyon dirus. This predator was the inspiration for the direwolves in fantasy author George R. R. Martin’s works. Does this mean scientists have successfully revived an extinct species? Is Jurassic Park no longer just science fiction? Let’s find out.

Since we’re talking about Jurassic Park, it’s important to note right away: no one resurrected dire wolves using blood preserved in a mosquito or frozen cells, like the dinosaurs in the popular film. That scenario is considered impossible because the DNA of ancient animals is too degraded. Instead, Colossal Biosciences used advanced DNA-editing and cloning technologies to replicate the traits scientists believe distinguished Aenocyon dirus from its closest modern relatives.

First, geneticists extracted DNA from two fossilized samples: a 13 000-year-old tooth from Ohio and a 72 000-year-old auditory bone from Idaho. As mentioned, a complete genome cannot be reconstructed from such fossils, but researchers filled in the gaps using the DNA of Aenocyon dirus’s closest relative — the gray wolf (Canis lupus).

Colossal Biosciences identified 20 differences in 14 genes responsible for dire wolf traits. These included a massive skull, powerful legs, pale fur, and a larger body.

Next, scientists took blood from gray wolves and edited the DNA using new technologies. The nuclei of the edited cells were transplanted into dog (Canis familiaris) egg cells, replacing the native DNA. The resulting embryos were then implanted into surrogate dogs.

Romulus and Remus were born in October of last year, and Khaleesi in January of this year. The pups were switched to bottle-feeding almost immediately. Currently, they live in a protected eco-park under constant observation.

Interestingly, even though the animals are raised by humans, they behave more like wild creatures than domestic dogs and try to avoid human contact.

As part of its effort to bring back the woolly mammoth (Mammuthus primigenius), Colossal Biosciences also unveiled a so-called "woolly mouse" last month. This genetically modified animal has traits characteristic of mammoths, the key one being thick golden-brown fur.

In theory, creating woolly mice brings us a step closer to reviving mammoths. Still, many experts remain skeptical of such achievements, citing future challenges and risks in experimenting with large mammals. From an ethical standpoint, the company’s work also raises concerns.

As for Romulus, Remus, and Khaleesi, their status as the first Aenocyon dirus representatives in 13 000 years is disputed by some researchers. Experts emphasize that these animals are not true dire wolves but genetically modified gray wolves. Yes, they possess certain traits of the extinct species, but that doesn’t make them its members.

In a BBC interview, paleogeneticist Dr. Nic Rawlence from the University of Otago stated:

Rawlence also added:

Romulus, Remus, and Khaleesi have no traces of ancient DNA. Their genes only mimic the hypothesized traits of Aenocyon dirus. This is noted by biologist Vincent Lynch of the University at Buffalo in a Euronews article:

It’s also important to point out that Aenocyon dirus and gray wolves aren’t all that closely related. Their ancestors split off from each other several million years ago and belong to different genera.

That said, Colossal representatives themselves admit Romulus, Remus, and Khaleesi are not clones of an extinct species. However, according to scientific director Beth Shapiro, that doesn’t really matter because the pups are “functional equivalents.” She believes what’s important is that they have the core traits of Aenocyon dirus.

As mentioned earlier, the company is also working on bringing back mammoths. Colossal plans to use available DNA fragments from woolly mammoths along with genes from modern Asian elephants to create a new animal. Scientists are editing genes related to fur, fat, and thermoregulation. The company aims to produce the first calf by 2028.

In addition, the genome of the Tasmanian tiger (Thylacinus cynocephalus), also known as the thylacine, has been decoded. In theory, it can now be recreated, but reproducing marsupials in a lab setting remains a complex process.

Another major challenge is implanting an embryo into a bird egg. If progress is made in this area, Colossal may try to revive the dodo (Raphus cucullatus) using its closest living relative — the Nicobar pigeon (Caloenas nicobarica).

One creature we likely won’t see again is the saber-toothed cat Smilodon. The DNA found is too damaged, and Smilodon has no close living relatives among today’s feline species.

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So, did scientists manage to bring back Aenocyon dirus? From a strictly scientific standpoint — no, the species remains extinct. The new pups are genetic imitations. On the other hand, the work done by Colossal Biosciences is still a major achievement that will influence the future of genetics. Exactly how remains to be seen.

What do you think? How do you feel about projects like this? Share your thoughts in the comments.