De-extinction Scientists Eyeing the Resurrection of Ice Age Giants: The Giant Bear and Beaver
In the world of de-extinction, where science fiction becomes reality, scientists are making groundbreaking strides toward reviving long-extinct species. What started with efforts to bring back the woolly mammoth and the Tasmanian tiger has now expanded to include other Ice Age giants—most notably the massive short-faced bear and the giant beaver. These incredible species, once thought lost to history, could be making a comeback thanks to advances in genetic engineering.
Colossal Biosciences Leading the Charge
At the forefront of these efforts is Colossal Biosciences, a U.S.-based biotechnology company pushing the boundaries of what’s possible in de-extinction. The company’s ongoing projects to revive the mammoth, the dodo, and the Tasmanian tiger have already garnered significant attention. But these prehistoric titans are just the beginning.
Beth Shapiro, the Chief Science Officer at Colossal, revealed that the company's ambitions go far beyond what’s already on the public radar. “I have a very long list of extinct animals I would love to see brought back,” Shapiro told reporters. Her enthusiasm for the project isn’t just about the spectacle of reviving ancient animals—she’s driven by a desire to understand more about their biology.
“I’d love to work on all of them because there’s so much we can learn from studying these creatures. Carnivores, in particular, would be fascinating,” Shapiro said. “One of my favorites is Arctodus, the giant short-faced bear, which stood about 14 feet tall. Imagine that! And the giant beaver, which could grow up to five feet tall—that would be quite a sight.”
Ice Age Giants: Arctodus and Castoroides
The species Shapiro mentioned, Arctodus (the short-faced bear), roamed North America during the Pleistocene epoch, which began about 2.5 million years ago and ended around 11,000 years ago. Arctodus is often considered the largest land-dwelling mammal that ever walked the North American continent, towering over humans even when on all fours. Standing upright, it reached a staggering 14 feet in height, making it one of the most fearsome predators of its time.
The demise of Arctodus is thought to have resulted from a combination of factors, including the extinction of large herbivores it preyed upon, competition with other predators such as brown bears, and the encroachment of early humans. With the loss of its food sources and increased competition, Arctodus ultimately couldn’t survive.
Alongside Arctodus was Castoroides, an enormous beaver species that lived in the wetlands of North America during the same period. This creature was no ordinary rodent—it reached up to five feet in height and had six-inch-long teeth that allowed it to fell trees and swim for extended periods. Castoroides became extinct about 10,000 years ago, likely due to changes in climate and the transformation of its wetland habitat. Fossil evidence shows that this giant beaver could remain underwater for extended periods, a feature that helped it thrive in its watery environment.
The Science of De-extinction
De-extinction is no longer the stuff of science fiction. Researchers like those at Colossal Biosciences are making rapid progress in reviving long-lost species through advanced genetic techniques. One of their most significant breakthroughs was the creation of pluripotent stem cells from Asian elephant skin cells earlier this year. These stem cells are vital in the effort to revive the woolly mammoth because they can be used to generate sperm and egg cells, helping ensure the survival of the Asian elephant, the mammoth’s closest living relative.
The Asian elephant shares about 99.5% of its genetic code with the woolly mammoth, which means scientists can fill in the missing gaps in mammoth DNA with Asian elephant genes. This work is crucial not only for bringing back the mammoth but also for aiding in the conservation of existing species.
The same process is being used to bring back other species, such as the dodo. Colossal has collected primordial germ cells (PGCs) from the Nicobar pigeon, the closest living relative to the dodo. These cells can be reprogrammed and modified to replicate the extinct bird’s DNA.
As Shapiro noted, the progress is nothing short of astounding. “Every time I enter the lab, I’m amazed at how fast things are moving. Our team working on the Thylacine [Tasmanian tiger] has made more unique genome edits than anyone before, and our work with the primordial germ cells from pigeons is moving faster than expected. It’s incredibly exciting.”
Beyond Jurassic Park: Real-World Applications of De-Extinction
While these projects may evoke images of Jurassic Park, the scientists behind them are not merely trying to recreate prehistoric zoos. Instead, the technology used in de-extinction has profound implications for biodiversity conservation and could help us better protect species currently on the brink of extinction.
One of Colossal’s primary goals is to ensure that no species alive today goes permanently extinct. As Shapiro explained, the ultimate benefit of de-extinction technology lies in its potential applications for human health and biodiversity conservation. "Bringing extinct species back is fascinating, but it’s important to understand they won’t be identical to the animals that originally roamed the Earth. We’re learning so much that can help prevent further extinctions," she said.
The techniques developed could be applied to endangered species such as the vaquita, a critically endangered porpoise, and the northern white rhino, which has only two remaining individuals. The company is also working to save the pink pigeon, a rare bird found in Mauritius.
These efforts are about more than just preventing the extinction of individual species—they could help restore entire ecosystems. As Shapiro explained, some ecosystems are on the verge of collapse because of the loss of a key species. "When an ecosystem loses a species, it can create a cascading effect where the entire habitat suffers. Restoring some of these interactions could help stabilize these fragile environments."
Hunting for Ancient DNA and the Ethical Line
In their pursuit of extinct species, Colossal’s researchers are not just working with recently extinct animals. They are also delving deeper into the past, seeking out ancient DNA from long-gone creatures. For example, fragments of DNA from two million years ago have been discovered in Greenland, raising the possibility of recovering genetic material from even older species.
However, Shapiro emphasized that there are limits to which species should be resurrected. She draws the line at Neanderthals and other human ancestors. “Neanderthals and Denisovans were people. They would need to give informed consent to be brought back, and clearly, that’s not possible,” she explained.
The Future of De-extinction
Colossal Biosciences, founded in 2021 by Harvard geneticist George Church and entrepreneur Ben Lamm, is at the forefront of this ambitious mission. With the launch of the Colossal Foundation, a non-profit arm of the company, they aim to further their efforts in saving and sustaining endangered animal populations.
The goal, as Shapiro puts it, is simple yet profound: “The ultimate goal of Colossal is to make extinction a thing of the past.”
As scientists continue to make strides in genetic research, the prospect of seeing animals like the giant bear and jumbo beaver once again walking the Earth may not be as far-fetched as it once seemed. But beyond the headlines and curiosity, these projects hold the potential to reshape our understanding of biology, ecosystems, and the delicate balance of life on our planet.
With the technology developing at such a rapid pace, we may be on the cusp of a new era in which extinction is no longer an irreversible fate for Earth’s species.