Colossal Biosciences Creates the Woolly Mouse, Genetically Engineered With Seven Mammoth-Inspired Gene Edits in a Key Step Toward the Woolly Mammoth’s Return

Seven modified genes produced a mouse with curled whiskers, wavy lighter-colored hair up to three times longer than normal, and mammoth-inspired body composition — results validated in 23 days rather than 22 months.

The mouse took 23 days. Colossal Biosciences has created the Colossal Woolly Mouse, born in October 2024 and genetically engineered with seven modified genes to achieve mammoth-inspired traits: curled whiskers, wavy lighter-colored hair up to three times longer than normal, and changes to body composition that would take 22 months to test directly in an elephant.

Computational analysis of 59 woolly, Columbian, and steppe mammoths, from 3,500 to over 1.2 million years old, helped identify the genetic targets. The goal is a cold-adapted animal capable of inhabiting Arctic ecosystems left vacant by mammoth extinction, with first calves targeted by 2028. Separately, the most complete Tasmanian tiger genome has been assembled by the lab, and pigeon primordial germ cell work for the dodo project is underway.

This story is based on original reporting by Mike Snider for USA TODAY. Read the full feature on USA TODAY → https://www.usatoday.com/story/news/nation/2025/03/04/colossal-woolly-mouse-mammoth-resurrection/80729483007/