Researchers Create Woolly Mice in Groundbreaking Mammoth Revival Project

In an ambitious effort to resurrect the woolly mammoth, researchers at Colossal Biosciences have made a significant breakthrough by creating a novel rodent species dubbed "woolly mice." This development, which was published on June 8, 2025, highlights the potential of advanced genetic engineering techniques in de-extinction science, yet it underscores the complexities and ethical considerations surrounding such endeavors.

The woolly mice exhibit a unique golden-brown coat that is three times thicker than that of ordinary mice, a result of targeted genetic modifications aimed at mimicking the physical traits of the long-extinct mammoth. Specifically, scientists focused on altering the genes responsible for hair length, texture, and color, as well as those thought to contribute to cold adaptation. However, the extent to which these modifications enhance the mice's ability to withstand frigid temperatures remains unverified.

Dr. George Church, a leading geneticist and co-founder of Colossal Biosciences, stated, “This initial step demonstrates how we can utilize genetic engineering to recreate traits of extinct species, serving as a foundation for further research.” The choice of mice for this experiment is rooted in their rapid reproductive cycle and well-mapped genetics, allowing for swift observation of the effects of genetic alterations. This approach contrasts sharply with the lengthy gestation of elephants, the closest living relatives of the mammoth, which could complicate research timelines.

Rather than fully resurrecting the woolly mammoth, the ultimate goal is to create a hybrid species that combines the DNA of the Asian elephant with that of the woolly mammoth. Given that the genomes of these two species share approximately 99.6% similarity, researchers believe that it is feasible to engineer a mammoth-elephant chimera possessing mammoth-like characteristics. This process employs induced pluripotent stem cells (iPSCs), which can differentiate into various types of cells, thereby facilitating the incorporation of mammoth genes into elephant cell lines.

The timeline for this project is ambitious; scientists aim to produce the first mammoth-elephant hybrid by late 2028. However, this endeavor has sparked considerable debate within the scientific community. Critics like Dr. Robin Lovell-Badge, a prominent stem cell researcher at the Francis Crick Institute in London, have expressed skepticism about the feasibility of such a project. He remarked, “While the woolly mice are an interesting development, transitioning from modified mice to successfully creating viable elephant embryos with mammoth traits poses an enormous challenge.”

The ethical implications of de-extinction projects are also a point of contention. Some experts advocate for the ecological benefits of reintroducing mammoths to their former habitats, particularly in Arctic regions, where these creatures could potentially aid in restoring grasslands and combating climate change. Conversely, others argue that resources devoted to resurrecting extinct species could be better spent on conserving endangered species currently facing extinction.

Despite these challenges, the creation of woolly mice represents a promising advancement in genetic research and de-extinction technology. The project is part of a broader scientific movement exploring the revival of other recently extinct species, including passenger pigeons and thylacines, utilizing rapid advances in genomic technologies. These efforts highlight the delicate balance between scientific innovation and ethical responsibility in the pursuit of reviving lost species. As the field of genetic engineering continues to evolve, the implications of these projects will undoubtedly shape our understanding of biodiversity and conservation strategies in the future.