Dire wolves exist mostly within the fictional worlds of fantasy books, movies, and games. You can find them in the Badlands of Warhammer, roaming the Forgotten Realms of Dungeons & Dragons, and traipsing after the Stark children in George R.R. Martin’s A Song of Ice and Fire.

Unlike most fantasy creatures, dire wolves actually existed once upon a time. They patrolled North America hunting giant ground sloths, bison, and other megafauna until about the end of the last ice age. Then they disappeared and their unique contribution to the North American landscape vanished with them. Until about six months ago.

“Dire wolves went extinct 12,500 years ago, until October of last year,” CEO of Colossal Biosciences Ben Lamm told SYFY WIRE. “We took a 13,000 year old tooth and a 73,000 year old skull, and we made puppies. We have three dire wolves.”

From ancient DNA to living animals: Bringing dire wolves back from extinction

Scientists knew from the fossil record that dire wolves shared a lot of characteristics with modern gray wolves, the major difference being their size. Dire wolves exhibit enhanced skeletal and muscular features, giving them pronounced shoulders, wider heads, larger jaws and teeth, and more muscular legs.

Their precise relationship with living canids has been the subject of some debate in recent years. In 2021, evidence suggested they may have been more closely related to modern jackals than to gray wolves, having split nearly 5 million years ago. Computational analysis of dire wolf DNA from two samples, a part of Colossal’s end-to-end de-extinction pipeline, suggests a more complex lineage involving an ancient split and more recent admixture, resulting in a close affinity to modern gray wolves.

According to Colossal, their analysis provided 500 times more information about the dire wolf genome than was previously available. Along the way, the company figured out how dire wolves and gray wolves are the same and how they’re different, then identified and engineered key genes leading to desired dire wolf traits. Here’s how it happened.

First, Colossal scientists extracted and sequenced ancient DNA from two dire wolf fossils. One was a 12,000-year-old tooth from Sheridan Pit, Ohio, and the other was a 73,000-year-old inner ear bone extracted from a skull found in American Falls, Idaho. Next, genomes were assembled from those samples and compared to living canids including, but not limited to, gray wolves. In the end, Colossal’s analysis found that the genomes of dire wolves and gray wolves are about 99.5% similar.

Key gene variants were identified, relating to things like coat color, fur thickness, and size. Next, Colossal took a donor genome from a gray wolf and edited 14 genes at 20 sites. Of those edits, 15 were the precise extinct gene variants found in ancient dire wolves. The other five were modern analogies found in gray wolves, and were chosen to support the animals’ welfare.

The computational analysis revealed, for instance, that dire wolves had white fur. It also revealed that the gene responsible had a non-zero chance of making the pups blind, deaf, or both. Using that gene may have resulted in an animal which was technically truer to its historical counterpart, but it would also have introduced an unnecessary risk. Instead, Colossal used an alternate gene found in modern gray wolves which produced the desired fur trait without the undesired side effect.

With their edited cell lines in hand, Colossal created clones using somatic cell nuclear transfer (the same process used in the creation of Dolly the sheep) and transferred the edited embryos to a surrogate. Biology took care of the rest.

The process is distinct from the sort of genetic magic on display in Jurassic Park (now available from Universal Pictures Home Entertainment). Rather than create a dire wolf from scratch using only ancient DNA and laboratory handwaving, Colossal used ancient DNA to identify the important ingredients in the dire wolf recipe, then used that information to engineer a gray wolf with those traits. We can and probably will quibble about whether or not that makes Colossal’s creations a “real” dire wolf. But if it walks like a dire wolf and quacks like a dire wolf…

Meet Romulus, Remus, and Khaleesi, the Colossal dire wolves

Colossal completed the de-extinction process not once but twice, resulting in a total of three wolves. Twin boys, named Romulus and Remus were born first, on October 1, 2024. “Two of our three [dire wolves] are 5 months old, the third is a female we named Khaleesi. She was born about 6 weeks ago,” Lamm said.

At the time of writing, Romulus and Remus live together in a secure 2,000 acre ecological preserve called Zone Alpha, in an undisclosed location somewhere in the northern United States. Khaleesi is being kept separately until she’s old enough and large enough to hold her own. The preserve is registered with the USDA and certified by the American Humane Society.

Daily, they eat about 6 pounds of meat — a mix of beef, horse, and deer — as well as about 3 cups of dry food. As they grow, they’ll eat more and more whole prey. Inside of Zone Alpha is a smaller 6-acre site where the wolves can be monitored and studied. It also includes an on-site veterinary clinic, wolf management facility, storm shelter, and natural den.

A full-time staff of 10 take care of the animals alongside a full-time veterinarian and dedicated animal hospital. The facility also features 9-foot zoo-grade fencing, redundant perimeter security, on-site security cameras, drone tracking, and a dedicated security team.

Let’s just hope Dennis Nedry isn’t on staff.

While you patiently await the release of Jurassic World Rebirth this summer, check out all the Jurassic Park and Jurassic World films, now available from Universal Pictures Home Entertainment.