In a world where science often feels larger than life, sometimes the biggest breakthroughs come in the smallest packages  —like a mouse with a woolly mammoth’s hairdo.

Dallas-based Colossal Biosciences, a company racing to revive extinct species, just unveiled its quirkiest creation yet: the “Colossal Woolly Mouse.” These tiny, curly-haired rodents aren’t time travelers from the Ice Age, but they’re a fuzzy milestone in the quest to bring back woolly mammoths.

The ‘Woolly’ mouse, left, and a normal mouse. Photo courtesy of Colossal Biosciences

“I’m excited,” Beth Shapiro, Colossal’s Chief Science Officer, said. “This is really our first validation that we actually can create living animals that have been genetically modified to have woolly mammoth traits.” The mice sport coats resembling the blonde, shaggy fur of mammoth mummies and carry genes linked to cold-weather fat metabolism. While prehistoric woolly mice never existed, these lab-engineered critters offer a speedy workaround for testing genetic tweaks. It also highlights a shift in STEM, she said.

It brings a different set of viewpoints that we really need,” Shapiro said. “We’re trying to solve some of the hardest problems in biology. It’s going to take diversity of experience.”

“Elephants have a 22-month gestation and then it takes another decade to reach sexual maturity. It doesn’t make any sense,” Shapiro said, laughing. Mice, with their 20-day pregnancies, are far more practical test subjects. The team focused on traits like insulating fat stores — critical for mammoths surviving icy landscapes —  and successfully integrated mammoth gene variants into the mice.

“In the next six months, we’ll see if our woolly mice are actually happier in cooler environments,” Shapiro added. If successful, the research could inform efforts to engineer cold-resistant elephants — a stepping stone to “de-extinct” mammoths. Beyond mammoths, Colossal is tackling two other vanished species: the dodo and the thylacine, or Tasmanian tiger.

Anna Keyte, leading the dodo project, emphasized modern challenges like bird flu. “It has been really bad for California condors, so one of the things we think about in our de-extinction pipeline is not only bringing back species we’ve lost, but making them resilient to the challenges of today,” she said.

Sara Ord, overseeing the thylacine revival, noted the ethical weight of undoing human-driven extinctions. “It’s an example of a human-caused extinction. How responsible are we to bring back this species that we drove away?” Ord said.

As for the woolly mice? Their future is bright — and possibly full of adoptive homes. “The CEO Ben Lamm made the comment, ‘Don’t let Sara know because she’s going to be adopting all of them,’” Ord said. “We all are not only passionate about the science, but passionate about the animals. And that holds all the way to the woolly mouse.”