Why science ethicists are sounding skepticism and alarm on ‘de-extinction’

In April, headlines crowed that pups named Romulus and Remus — and Khaleesi — heralded the return of the dire wolf. But at a GW Law webinar, neuroscientist and executive director of The Kimmela Center for Animal Advocacy Lori Marino, Ph.D., urged caution, drilling into the fine print, calling them “proxies.” “What is being produced” is “not the actual extinct species,” she said. In other words, the pups are designer CRISPR-minted hybrids.

Heather Browning, Ph.D. a lecturer in philosophy at the University of Southampton, criticized the lack of focus on animal welfare amidst the headlines. “No one’s really thinking about the dire wolves themselves,” Browning said. “And I think that is an oversight.”

The wolves entered the world after scientists at the startup Colossal edited genes in gray wolf cells, aiming to match traits derived from ancient dire wolf DNA recovered from fossils. Using cloning techniques, they created numerous embryos from these edited cells, which were then transferred into domestic dog surrogates. Four pups initially survived, reportedly delivered via C-section late in 2024, while one died shortly after birth.

The industry still won’t disclose how many embryos or surrogate dogs were lost along the way, a silence that worries critics who see de-extinction as Jurassic glamor masking real-world costs.

They never tell you what it took to get those creatures. —Marino

The process involved significant attrition, a common issue in de-extinction attempts. Marino pointed to the early 2000s effort to resurrect the Pyrenean ibex, Celia, where only one clone was born from hundreds of attempts, only to die within minutes. “This gives you an idea of the kind of inverted pyramid of numbers that’s behind all of these so-called successes, and it’s an animal welfare issue,” Marino stated.

The dire-wolf litter is only Act I of a much bigger resurrection pitch. Colossal is also chasing the woolly mammoth and the dodo, while public wish lists include the passenger pigeon and the Tasmanian tiger. Marino worries the wish list won’t stop there. “There has been talk about de-extincting Neanderthal people, and I think we can all agree we’re getting to a point where we need to take a step back,” she warned.

Creating these “proxies,” Marino noted, citing IUCN concerns, carries the risk of unleashing novel organisms that could “harm ecosystems” or “become ‘invasive’,” potentially driving new extinctions rather than reversing old ones. The process of tinkering with ancient and modern genomes might also have unforeseen pathological consequences. “[There is risk of] the creation of novel disease vectors [or the] inadvertent resurrection of Ancient diseases,” Marino cautioned. Because these CRISPR-created animals are fundamentally “hybrids,” their long-term effects remain dangerously “unpredictable,” raising the spectre of irreversible ecological damage.

Who’s teaching them to be wolves? —Browning

Pushing further, she invoked a pop-culture cautionary tale: “We can get into that kind of Jurassic Park scenario where you have something new — not a dinosaur, not a reptile, not a bird, but something else entirely, a new life form, with all the risks associated with that,” Marino said. The message from both ethicists: before we celebrate prehistoric comebacks, we’d better tally the modern-day bodies — and consider whether the next headline could read more like science-fiction horror than scientific triumph.