During the Ice Age, dire wolves roamed the Americas until going extinct more than 10,000 years ago. They were well-known for being enormous—25% bigger than gray wolves—and for hunting big game like horses and bison.

Dire wolf twins Remus and Romulus on the Iron Throne prop from Game of Thrones , loaned by owner Peter Jackson.

By fusing gray wolf genes with ancient DNA from fossils, Colossal Biosciences, a genetic engineering firm, says it has "de-extincted" dire wolves and produced three pups.

Dire wolf twins Remus and Romulus on the Iron Throne prop from Game of Thrones , loaned by owner Peter Jackson.

DNA was taken from a 72,000-year-old skull and a tooth that was 13,000 years old. Twenty gene modifications were done to gray wolf DNA using CRISPR in order to replicate dire wolf characteristics such as bigger teeth and white fur.

Dire wolf twins Remus and Romulus on the Iron Throne prop from Game of Thrones , loaned by owner Peter Jackson.

In late 2024 and early 2025, the pups—named Romulus, Remus, and Khaleesi—were born. They inhabit a 2,000-acre park and are anticipated to reach a weight of 130–150 pounds, making them significantly larger than gray wolves.

Dire wolf twins Remus and Romulus on the Iron Throne prop from Game of Thrones , loaned by owner Peter Jackson.

Experts contend that these are genetically modified gray wolves rather than real dire wolves. Twenty gene modifications might not be enough to completely reconstruct the species because dire wolves and gray wolves split millions of years ago.

Dire wolf twins Remus and Romulus on the Iron Throne prop from Game of Thrones , loaned by owner Peter Jackson.

"Game of Thrones" made dire wolves famous as Stark's friends. After meeting the pups, Colossal investor George R.R. Martin connected fantasy to this scientific achievement.

Dire wolf twins Remus and Romulus on the Iron Throne prop from Game of Thrones , loaned by owner Peter Jackson.

Colossal intends to use this innovation to help endangered species like the red wolf. While some regard it as a step toward reviving lost biodiversity, others warn of ecological concerns.

Dire wolf twins Remus and Romulus on the Iron Throne prop from Game of Thrones , loaned by owner Peter Jackson.