Colossal Biosciences Edges Closer To Reviving The Woolly Mammoth With "Woolly Mice"

Colossal Biosciences is on a quest to bring back the woolly mammoth. On March 1, 2025, the Texas-based startup came one step closer to its goal with the creation of genetically-modified "woolly mice." Featuring thick, golden fur and curled whiskers, the rodents have characteristics similar to those of the woolly mammoth.

The team, led by Beth Shapiro, started by finding the genes that made mammoths unique. To do this, they compared ancient mammoth DNA to that of African and Asian elephants, their closest living relatives. Key differences included genes linked to long, woolly hair and fat metabolism. Both were crucial for surviving the cold weather. Next, they searched for similar genes in mice that affect things like coat thickness, color, and fat storage.

The team then used gene-editing tools to modify seven genes in mice. Six were related to hair growth, texture, and metabolism. The result? Adorable mice with thick, woolly coats. These rodents also developed fat deposits similar to those that helped mammoths endure frigid weather. However, it is unclear whether they can withstand cold better than regular mice. The scientists plan to test this in the coming months.

The woolly mice are a great start to the company's goal of reviving the woolly mammoth, but many challenges remain. While the gene-editing tools worked on mice, they are not advanced enough to work on elephants. For example, unlike rodents, elephants have sparse hair. This will make it much more difficult to genetically modify them for a woolly coat.

Critics argue that even if Colossal succeeds, the result will not be a true woolly mammoth. Instead, it would be a modified elephant with mammoth-like traits. Whether the company's vision becomes a reality remains to be seen. For now, creating woolly mice is an exciting milestone.

"For us, it's an incredibly big deal," Shapiro said.

Resources: NPR.com, Livescience.com, Colossal.com