Colossal’s “artificial egg” fuels de-extinction debate

Colossal’s artificial – Colossal Biosciences says its semi-permeable “artificial egg” can hatch birds—including 26 chickens—and positions the technology as a step toward “resurrecting” species such as New Zealand’s giant moa and the dodo from Mauritius. But prominent researchers ques

On paper, it sounds like the kind of breakthrough that rewrites biology textbooks: Colossal Biosciences has developed an “artificial egg” meant to recreate key conditions inside an egg, and the company says it can hatch embryos from chickens.

The company’s pitch goes further. It calls the technology a step toward “resurrecting” extinct birds. including New Zealand’s South Island giant moa and Mauritius’s famous dodo. That framing immediately drew pushback from scientists who say the word “de-extinction” misleads the public—and that the hard parts of extinction aren’t solved by incubators.

Victoria Herridge, an evolutionary biologist at the University of Sheffield in England, put the point bluntly. “Nothing will ever bring back a mammoth; nothing will ever bring back a dodo,” she said. “Extinction really is forever.”

Colossal’s announcement centers on what it claims to solve for birds: the embryo needs an environment that resembles an egg’s interior. not just a lab-produced genetic instruction set. The company argues that its system can replicate that space. In its press release. Colossal described “a semi-permeable silicone-based membrane housed inside a rigid hexagonal support cup”—an artificial environment designed to keep moisture inside the embryo while delivering oxygen and keeping out contaminants.

Colossal says the approach, in theory, could work for any egg size, whether it hatches a hummingbird or a moa. It also says it has successfully hatched 26 chickens.

Yet the details that would let independent scientists judge how strong the result really is are missing. The release did not say how many embryos were originally obtained. how many embryos were loaded into the artificial eggs. how long the chicks survived. or what could be said about their health other than that the chicks were “healthy” when they hatched. Colossal Biosciences did not respond to a request for comment.

The company also said it has “not released a peer-reviewed paper or publicly available dataset accompanying the artificial egg results. Independent scientists have not yet evaluated the methodology.”

For researchers focused on embryos and breeding, the core question is whether the system meaningfully improves on what already exists.

Mike McGrew. a professor specializing in embryology at the University of Edinburgh. said the current benchmark is low hatching success from earlier “artificial casings” that enable chicken or quail embryos to grow into full-fledged chicks. “The hatching rate for those systems remains low, making them inefficient and unpredictable,” he said. “If Colossal’s hatch rate is higher. then that would be useful.” He added that the technology could be particularly helpful to conservation if it can be expanded to species with larger eggs. including Emus and species of ducks.

Nic Rawlence. an evolutionary geneticist at the University of Otago in New Zealand. suggested a different target entirely—one that steers away from resurrecting whole lost lineages. He told Nature he could see the artificial eggs potentially supporting breeding of the Kākāpō (Strigops habroptilus). a flightless parrot that is endangered on New Zealand. “That’s what Colossal should be focusing on rather than bringing in the whole de-extinction angle,” he said.

Not everyone is convinced that the technology is the major leap Colossal is implying.

Chris Elphick, an ornithologist at the University of Connecticut, said Colossal’s technique, as described, appears to involve pouring the contents of a natural chicken egg into an artificial shell. “You could just leave the embryo in the egg that it’s already in for any existing species,” he said.

Even if the egg-like system works better than alternatives, some experts argue it may still be the wrong lever to pull.

Michael Parr. president of the American Bird Conservancy. pointed out that many existing captive breeding programs are already producing growth in populations without artificial eggs. including those in place for the critically endangered ‘Akikiki in Hawaii. Parr said using artificial eggs may be a more expensive route to reach the same result.

For Parr, the bigger challenge is what happens after breeding succeeds. “A lot of these species. it’s not so much the breeding that’s not working. it’s what happens when you reintroduce them to the wild and what were the conditions that caused them to become rare or near extinction in the first place. ” he said.

Elphick echoed that skepticism by linking the technical hurdles to practical ones. “Apart from the technical issues, there’s the practical issues,” he said. “Where [are] you going to put them? [Humans] destroyed their habitat; there’s a reason they’re extinct.”

Herridge returned to the framing itself. She agreed that conservation should be the priority and argued against “de-extinction” as the way to present projects like Colossal’s. “They’re synthetic biology experiments at the moment,” she said. “They’re actually about creating novel organisms, something completely new.”.

Colossal has said it might be able to match specific traits associated with a lost species. The company’s chief science officer. Beth Shapiro. said in an interview with Scientific American when Colossal announced three “dire wolf pups” that they were “actually gray wolves sporting 20 genetic edits.” Shapiro said. “We want to create functional versions of extinct species.” She also said. “We don’t have to have something that is 100 percent genetically identical.” The company has also announced a program targeting the extinct bluebuck antelope.

Herridge argues that even that kind of targeted approach runs into a knowledge gap about ecology. Scientists, she said, don’t know enough about the ecology of any lost species to replicate its function in the ecosystem.

And she ties the critique to a broader biodiversity reality that conservationists say cannot be put on hold. “It doesn’t deal with any of the underlying problems that are currently facing our wild places and biodiversity today,” Herridge said.

The company’s supporters may see the artificial egg as an enabling tool—something that could eventually improve breeding outcomes. The company’s critics see something else: a high-profile. emotionally charged promise that has not yet been backed by peer-reviewed methods and that risks diverting attention from the conditions that still drive species toward extinction.

Editor’s Note (5/21/26): This sentence was edited after posting to better clarify Victoria Herridge’s comment.

Colossal Biosciences artificial egg de-extinction moa dodo kākāpō conservation embryology synthetic biology Beth Shapiro genetic edits bluebuck antelope