The pursuit of de-extinction has broken new ground yet again, as three young wolves are carrying on the legacy of the dire wolf species that disappeared from Earth around 12,500 years ago. Dallas-based Colossal Biosciences, the company leading the de-extinction charge, recently declared that the dire wolf has returned for good.
The three wolves brought to life by the company — Romulus, Remus, and Khaleesi — emulate many unmistakable dire wolf characteristics, seen in their size, skull shape, and stunning white coats. This breakthrough was made possible with technology that allowed scientists to alter gray wolf genes so they would mirror extinct dire wolf genes; while serving as a stepping stone for future de-extinction endeavors, the dire wolf project may also pave the way for the future of conservation.
When Did Dire Wolves Live?
The dire wolf (Aenocyon dirus) once roamed throughout North and South America during the Late Pleistocene, facing extinction near the end of the last ice age. The species may have been doomed by its diet; it dined mostly on megaherbivores, many of which would vanish in the Americas starting around 13,000 years ago, leaving dire wolves with less prey to eat.
Long after their demise, dire wolves rose up the ladder of pop culture thanks to their fictionalized appearance in the Game of Thrones series. While fantasy fans have become familiar with the dire wolf, the species' esteem does not stop there; through generations of oral tradition, the dire wolf has also served as a mythological cornerstone for the MHA Nation, a federally recognized Native American Nation in North Dakota.
Read More: Fact or Fiction: Are Mysterious Dire Wolves Real?
Reviving Extinct Genes
Colossal’s dire wolf project started with DNA extraction from two fossils — a 13,000-year-old tooth found in Ohio and a 72,000-year-old inner ear bone found in Idaho. As scientists analyzed these fossils, they encountered new revelations on dire wolf evolution. The company announced in a statement that gray wolves and dire wolves share 99.5 percent of their DNA code based on genetic analysis, although prior studies have previously asserted that dire wolves may be related more closely to jackals rather than gray wolves.
Scientists at Colossal used DNA from the two fossils to pinpoint parts of the dire wolf genome that gave the species its unique traits. To bring this gene expression back into the modern era, they had to first acquire a donor gray wolf donor genome through a non-invasive blood drawing procedure that gave them epithelial progenitor cells (EPCs).
They then performed multiplex gene editing, a process that allowed them to edit 20 sites across 14 genes in the gray wolf genome. Among these edits, 15 of them targeted extinct dire wolf variants, activating gene expressions that haven’t been seen for over 10,000 years. It is worth noting, though, that throughout this process, dire wolf DNA was only used as a reference point for edits of the grey wolf genome.
The scientists cloned embryos containing these edited genes and then surgically put them inside a surrogate dog that would eventually birth the wolves.
A Growing Pack
Romulus and Remus, now about 6 months old, were the first to be born from this project. Spending their days at a 2000+ acre preserve, they've already passed many developmental milestones and are now weighing upwards of 80 pounds. Khaleesi, only 2 months old at this point, is still considered too young to join Romulus and Remus, but she will inevitably join the growing pack once she's large enough.
The wolves will continue to be monitored by care staff at the preserve while scientists keep an eye on their progress over time. Beth Shapiro, Colossal’s Chief Science Officer, says the dire wolf is known to have been an adaptable species since it has lived through warmer interglacial periods and colder ice ages.
“They’re clearly adaptable, behaviorally plastic animals, and as they grow and as they start to interact with their environment, we’re going to learn about this plasticity,” says Shapiro. “We’ll learn about the way that they interact with different types of habitats, different types of temperatures and climate regimes.”
According to Matt James, Colossal’s Chief Animal Officer, the company has discussed expanding the pack size to around eight wolves to fit a more natural wolf pack structure.
Upholding Conservation and Biodiversity
The identity of Romulus, Remus, and Khaleesi has some independent scientists voicing qualms about the authenticity of dire wolf de-extinction — whether these wolves are truly the dire wolves of the distant past or just gray wolves that have been genetically modified to appear as dire wolves.
Shapiro notes that when it comes to de-extinction, Colossal is “not about creating perfect genetic copies of something that used to be there, but about restoring lost ecological functions and enhancing biodiversity.”
Despite the air of hesitancy partially clouding the results, the project strikes a hopeful chord for wildlife conservation. The same technological advancements used by Colossal to give life to Romulus, Remus, and Khaleesi have also allowed the company to birth two litters of cloned red wolves, a critically endangered species native to the southeastern U.S.
Gene editing, according to the company, will become an important tool to help species endure a changing world. A vital goal of their core de-extinction projects — involving the dire wolf, the woolly mammoth, and the thylacine (also known as the Tasmanian Tiger) — is to direct attention toward bolstering conservation and reducing loss of biodiversity.
“I think what Colossal can offer with our technologies is opportunities to help recover populations at scale in places where they should be reintroduced responsibly in a way that can be focused on coexistence,” says James.
Read More: With Bushy Hair, This Engineered Woolly Mouse Could Help Revive the Woolly Mammoth
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
National Park Service. Dire Wolf
PNAS. Overkill, glacial history, and the extinction of North America’s Ice Age megafauna
The University of Adeliade. Ancient DNA research reveals evolutionary secrets of Game of Thrones dire wolves.
Jack Knudson is an assistant editor at Discover with a strong interest in environmental science and history. Before joining Discover in 2023, he studied journalism at the Scripps College of Communication at Ohio University and previously interned at Recycling Today magazine.
