Jan 25, 2025

I write about the world of biology. getty Continuing its audacious blend of ambition and cutting-edge science, Colossal Biosciences has secured $200 million in Series C funding to accelerate its groundbreaking efforts to resurrect the woolly mammoth. The company is also researching ways to bring back the Dodo and the Tasmanian Tiger. The Dallas-based biotechnology company, founded in 2021, is spearheading the nascent field of de-extinction, the process of restoring long-lost species to their natural habitats and, potentially, reshaping ecosystems. The woolly mammoth, a giant that roamed the icy expanses of the planet during the Pleistocene epoch, became extinct around 4,000 years ago and is at the center of Colossal’s mission. It’s a mission that is less a nostalgic yearning for a prehistoric past than it is a solution to combat climate change, the company’s founders have said. By reintroducing mammoths to Arctic environments, they hope to rejuvenate grasslands and reduce permafrost thaw—a major source of methane emissions. The potential ripple effects of such an ecological intervention have raised profound ethical and scientific questions but have nonetheless captivated researchers, investors and the public alike. MORE FOR YOU Colossal Bioscience’s approach to de-extinction is rooted in cutting-edge advances in genetic engineering and synthetic biology. The process begins by extracting DNA from preserved specimens of extinct species. For the woolly mammoth, scientists analyze DNA recovered from frozen remains to identify the genetic differences between the mammoth and its closest living relative, the Asian elephant. With 99.6% shared DNA, the Asian elephant is the woolly mammoth's closest living relative getty Then, using CRISPR-Cas9, a revolutionary gene-editing tool, researchers splice mammoth-specific genes into the genome of the Asian elephant to create a hybrid embryo. This hybrid embryo, which would be gestated in a surrogate elephant or synthetic womb—another technology Colossal is building that may have applications in fertility treatment—is designed to exhibit traits such as long fur, subcutaneous fat and cold tolerance, all hallmarks of the woolly mammoth. The same principles apply to the resurrection of the Tasmanian tiger and the dodo, with scientists relying on the closest living relatives of these species, such as the numbat and Nicobar pigeon, respectively. Why The Woolly Mammoth? As explained previously, the woolly mammoth has the potential to not just be a symbol of the Ice Age but also as a climate-change combatant . Colossal’s vision for reintroducing mammoths into the tundra ecosystem hinges on their ability to replicate behaviors that promote grassland regeneration. Mammoths’ trampling could compress snow layers, reducing heat transfer to the soil and slowing permafrost melt. Moreover, they might encourage the growth of grasslands that reflect more sunlight than darker forest canopies, thus mitigating the albedo effect—a measure of how well the Earth reflects sunlight. It’s an ecological experiment that’s rooted in the theory of Pleistocene rewilding, which posits that restoring extinct megafauna could revive degraded ecosystems. Skeptics, however, warn that such interventions could yield unintended consequences, including competition with existing species and other unforeseen ecosystem dynamics. The Dodo and Tasmanian Tiger Projects While the woolly mammoth project garners most of the attention, Colossal’s work on the dodo and Tasmanian tiger underscores the broader implications of de-extinction. The dodo, a flightless bird native to Mauritius, went extinct in the late 1600s due to overhunting and habitat destruction. Reviving it could serve as a case study in restoring island ecosystems, which are particularly vulnerable to species loss. The Tasmanian tiger, or thylacine , presents another compelling challenge. Extinct since the 1930s, this carnivorous marsupial once played a crucial role in its ecosystem. Its reintroduction could help control invasive species in Tasmania. Colossal plans to leverage the thylacine’s genome , pieced together from museum specimens, to create a living, breathing representative of the species. The Road Ahead The excitement around de-extinction is tempered by significant ethical and practical concerns. Critics question whether resurrected species can truly be considered the same as their extinct counterparts or if they are mere approximations. Furthermore, the potential risks of introducing genetically engineered organisms into the wild—from ecological disruptions to disease spread—will be the subject of careful consideration. Another challenge lies in securing the habitats necessary for these species to thrive. For instance, Asian elephants, already endangered, face numerous threats and their use as surrogates raises questions about animal welfare. The success of de-extinction efforts could divert resources from conserving endangered species that still have viable populations as well. Either way, Colossal Biosciences—now valued at $10.2 billion after its recent round of funding—is poised to redefine conservation biology. De-extinction offers a tantalizing glimpse into a future where science could restore lost wonder but it also compels us to reflect on our responsibility to protect what remains. Does the idea of bringing these long-extinct animals back to life fill you with curiosity and awe? Take this test and find out if you care for animals the same way you care for people: Animal Attitude Scale