Romulus and Remus, the two male dire wolves born through genetic engineering, turned a year old on October 1, 2025. The dire wolves, created by Colossal Biosciences, are the first of their kind in more than 13,000 years.
The wolves’ first birthday was marked with a meat-based “cake” made by Mishka, a San Francisco-based luxury dog bakery, and a dedicated song, “Happy Birthday Dire Wolf,” from veteran songwriters Stan Bush and Lenny Macaluso, USA Today reported.
First litter and a growing pack
The male wolves were born in October 2024, followed by a female named Khaleesi in January 2025, as per the company’s official website.
In an email exchange with USA Today, company officials say all three dire wolves are healthy, active, and showing signs of natural hunting instincts. “Remus is fearless and bold, while Romulus is inquisitive, cautious, and confident,” said Matt James, Colossal’s chief animal officer, who witnessed their birth.
Researchers used the DNA extracted from a 72,000-year-old skull and a 13,000-year-old tooth to build a genome. They then edited gray wolf DNA to bring back the traits specific to dire wolves. The fertilized eggs were then implanted and born to their surrogate dog mothers. Although it is not a 100% match for their ancestors, they are as close as it can be with biotech continuing to advance further.
{{/usCountry}}Researchers used the DNA extracted from a 72,000-year-old skull and a 13,000-year-old tooth to build a genome. They then edited gray wolf DNA to bring back the traits specific to dire wolves. The fertilized eggs were then implanted and born to their surrogate dog mothers. Although it is not a 100% match for their ancestors, they are as close as it can be with biotech continuing to advance further.
{{/usCountry}}Colossal says more dire wolves are coming. “We are working with our internal team and external network of advisors to make plans to grow the pack,” James said. The goal is a group of up to eight animals.
Tracking growth and behavior of Dire wolves
Dire wolves are often associated with pop culture through Game of Thrones or even the popular Grateful Dead song titled ‘Dire Wolf,’ but they were once real predators across North America. They went extinct about 13,000 years ago.
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At one year old, Romulus weighs about 120 pounds and Remus just under 115. They are expected to reach 130–140 pounds when fully grown. This summer, the males were introduced to their sister, which CEO Ben Lamm called “an amazing socialization opportunity.” The trio has already displayed pack behaviors and even managed to catch a rabbit inside their preserve.
The dire wolves are fed once daily, consuming more than five pounds of meat each, ranging from deer to rabbits. They also chew the bones and occasionally hunt small rodents on the preserve.
The preserve is staffed by 10 animal care workers, with live cameras, drones, and an on-site veterinary clinic for constant monitoring.
For Colossal, the milestone confirms that genetic editing worked. Romulus, Remus, and Khaleesi are only the beginning as they plan to bring back the ‘Wooly Mammoth’ next.
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FAQs
Who are Romulus and Remus?
They are the first two male dire wolves born through Colossal Biosciences’ genetic engineering project in October 2024.
What is a dire wolf?
Dire wolves were large predators that lived in North America before going extinct about 13,000 years ago.
How were the dire wolves created?
Scientists used ancient DNA to edit gray wolf genes, and the embryos were carried by surrogate dogs.