In a groundbreaking development that has captured the imagination of scientists and the public alike, researchers at Colossal Biosciences have engineered a genetically modified mouse with traits reminiscent of the long-extinct woolly mammoth.
Dubbed the “woolly mouse,” this small rodent represents a significant milestone in the ambitious quest to resurrect the iconic Ice Age giant, which vanished from the Earth approximately 4,000 years ago.
According to a CNN report published on March 4, 2025, the woolly mouse boasts “curly whiskers and wavy, light hair that grows three times longer than that of an ordinary lab mouse.”
Colossal Biosciences, a Dallas-based biotech company, engineered this rodent by editing seven genes to incorporate mammoth-like traits such as long, thick fur and adaptations potentially linked to cold tolerance.
The company’s scientists identified genetic variants unique to woolly mammoths by comparing their DNA to that of the Asian elephant, the mammoth’s closest living relative, and then introduced corresponding changes into mouse embryos.
Dr. Beth Shapiro, Colossal’s chief science officer, described the creation as “an important step toward validating our approach to resurrecting traits that have been lost to extinction,” as quoted in the CNN article.
AP News, in a story also dated March 4, 2025, elaborated on the process, noting that the team targeted genes related to hair texture and fat metabolism—qualities believed to have helped mammoths thrive in the Arctic.
The resulting mice, nicknamed “Colossal woolly mice,” sport golden, shaggy coats and curled whiskers, a stark contrast to their standard lab counterparts.
The outlet emphasized that this experiment serves as a testing ground to confirm whether such genetic edits could eventually be applied to Asian elephants, the species Colossal aims to transform into a mammoth-like hybrid.
Colossal Biosciences has made no secret of its ultimate objective: to produce a living, walking elephant-mammoth hybrid by 2028.
The Telegraph reported on March 4, 2025, that the woolly mouse is a “genetically engineered pioneer” bred to test the feasibility of introducing multiple mammoth traits simultaneously.
Ben Lamm, Colossal’s CEO, hailed the achievement as a “watershed moment,” stating, “By engineering multiple cold-tolerant traits from mammoth evolutionary pathways into a living model species, we’ve proven our ability to recreate complex genetic combinations.”
The company argues that reintroducing such creatures to the Arctic could help restore ecosystems by slowing permafrost thaw, a process that releases significant carbon into the atmosphere.
This isn’t the first time Colossal has made headlines. CNN previously reported in 2024 on the company’s success in deriving stem cells from Asian elephants, a critical step in manipulating their DNA.
The woolly mouse builds on that foundation, serving as a proof-of-concept for the gene-editing techniques that will be necessary to achieve the larger goal.
As George Church, a Harvard geneticist and Colossal co-founder, told CNN, the project demonstrates “remarkable progress” in precise genome engineering.
Despite the excitement, the development has sparked debate among scientists and conservationists.
AP News quoted Christopher Preston, a wildlife and environment expert at the University of Montana, who cautioned that “you’re not actually resurrecting anything—you’re not bringing back the ancient past.”
Critics argue that the resulting creatures will be hybrids, not true mammoths, and question whether the resources—Colossal has raised over $400 million, per AP News—could be better spent on conserving living species.
The Telegraph echoed these concerns, citing British scientist Dr. Louise Johnson, who described the woolly mouse as “a bit like looking back at the past, but with a highly selective telescope.”
She warned that the ethical implications of reviving extinct species remain unresolved, particularly regarding their introduction into modern ecosystems.
Similarly, CNN noted skepticism from experts like Tori Herridge of the University of Sheffield, who questioned whether scientists fully understand the genetic changes needed to make an elephant fit for Arctic life.
