Extinction and De-Extinction: History, Ethics, Future

Extinction is a concept deeply ingrained in human understanding from a young age, often encountered through toys, museums, and stories like that of the dinosaurs. However, the idea that species could vanish permanently was not always accepted.

The Shifting Understanding of Extinction

Until the late 18th century, European and American naturalists and theologians largely believed species were stable, divinely created, and unchanging. The notion of species changing, evolving, or disappearing was considered implausible, even impious, as it implied a flaw in nature. When species were thought lost, like the dodo, it was often attributed to human actions, not a natural process, and described as "extirpation," "eradication," or "extermination." Naturalists often assumed lost species were simply undiscovered elsewhere.

This perspective began to change in the late 18th and early 19th centuries. Georges Cuvier's comparative anatomical research on mammoth fossils and living elephants during the French Revolution was pivotal. He demonstrated that mammoths were a distinct, extinct species, separate from Asian and African elephants. This detailed research convinced geologists that Earth had once harbored an ancient world populated by now-lost "monsters" like mammoths, mastodons, and giant sloths.

The Discovery of Ancient Humans

Throughout the 1820s and 1830s, geologists suspected humans had existed much earlier than previously believed. Cuvier, however, died believing no human fossils had ever been found, thus his vision of deep time remained unpopulated by humans. Early discoveries of seemingly old human bones were often dismissed as hoaxes or not ancient enough to be considered fossils. The reluctance to accept animal extinction was amplified when considering human extinction.

This changed in 1856 with the discovery of Neanderthal remains near Dusseldorf, Germany. Initially discarded, they were recognized as human fossils after considerable debate. In 1859, the same year Darwin published On the Origin of Species, Sir Charles Lyell announced that ancient humans and mammoths had coexisted.

The Neanderthal skull, with its distinctive brow ridge, sparked questions about whether it represented a different species or a physiological anomaly. Thomas Henry Huxley, in his 1863 collection of essays Man's Place in Nature, compared the Neanderthal skull to those of modern colonized peoples. He confirmed the bones were fossils and controversially suggested that modern colonized peoples were examples of "stone age hunters," effectively collapsing the time between Neanderthals and contemporary indigenous populations. This led to the prejudicial stereotype that certain peoples were "living in the stone age," providing a supposed window into ancient human life. This vision of the human past dominated 19th-century debates and laid the foundation for enduring stereotypes.

The Rise of Modern Extinction Concerns

By the mid-19th century, ancient extinctions of animals and humans were well-established. Naturalists then began to worry about present-day extinctions, particularly species like the great auk. This seabird, resembling a penguin but related to guillemots, was hunted for centuries. In the 18th century, industrialized hunting for bedding caused its population to plummet. The last pair of great auks was killed by collectors in 1844 off Iceland, highlighting how rarity increased commercial value rather than prompting conservation.

Extinct birds like the great auk and dodo captured public imagination in the 1860s, partly due to children's literature like Charles Kingsley's The Water-Babies and Lewis Carroll's Alice in Wonderland. Ornithologist Alfred Newton, despite suspicions of the great auk's loss, searched for living specimens in 1858. His unsuccessful voyage, coupled with conversations with islanders, convinced him that commercial exploitation had driven the great auk to extinction. This was a shocking realization for many naturalists, as it suggested humans could rapidly exterminate a widely distributed species, unlike island-dwelling species with small populations.

Newton began to view extinction as a progressive process of loss triggered by human destructiveness, a significant shift from seeing it as a prehistoric reality. This understanding led him to advocate for wildlife protection, contributing to the first British legislation for seabird protection in 1869 and involvement with the Royal Society for the Protection of Birds.

Other naturalists soon shared Newton's view of "unnatural extinction." Hunters and collectors in Europe and North America witnessed the decline of big game, issuing warnings about wildlife's future. North American bison populations, for example, plummeted from an estimated 30-60 million in the late 1700s to just 456 by the 1890s. Shockingly, this killing was sometimes deliberate, partly to control Native American populations and open land for colonization. The rarity of species also fueled collection by museums, rather than conservation efforts.

Yellowstone National Park became the last sanctuary for bison by the 1880s. Dedicated reservations, driven by former hunter William Temple Hornaday, led to their slow recovery in the early 20th century. This marked one of the earliest successful interventions to save a species from the brink, demonstrating that conservation was not an automatic response to rarity.

The Passenger Pigeon: A Stark Warning

While bison were saved, others were lost to commercial exploitation, most famously the passenger pigeon. These birds formed the largest flocks ever known, with peak populations estimated at 3 to 5 billion, representing 25-40% of all North American birdlife. John James Audubon famously described a flock in 1813 that took three days to pass, numbering over a billion birds. Another ornithologist witnessed a flock estimated at 2.2 billion, which, if flown beak-to-tail, would have circled the Earth's equator 22.6 times. Yet, within 50 years, these immense flocks were gone.

Efforts to save the species were minimal; naturalists were more inclined to capture, study, and preserve remains than to conserve survivors. The population dwindled to just two individuals, George and Martha (named after George and Martha Washington), at the Cincinnati Zoo. George died in 1910, leaving Martha as the world's first "celebrity endling"—the last living member of her kind. Ornithologists made pilgrimages to see her. Martha died on September 1, 1914, just weeks before World War I began. Her body was preserved and shipped to the Smithsonian for autopsy, serving as a stark reminder of human destruction.

The rapid and massive loss of passenger pigeons became a powerful tale of human exploitation, but recent attempts to resurrect the bird raise profound questions about our relationship with other species and the meaning of extinction itself.

De-extinction: A New Frontier

The concept of de-extinction, driven by rapid technological advancements in genetic engineering, has gained significant interest. This involves using "frozen arcs"—collections of frozen specimens preserved in biobanks—as an insurance policy against loss.

The ability to freeze biological tissues without damage, discovered in 1949 by Christopher Polge, Audrey Smith, and Alan Parks, revolutionized scientific research. They found that adding glycerol prevented ice crystallization, allowing cells to remain intact after thawing. This technique quickly found application in animal husbandry, with the first calf born from frozen bull semen, Frosty, in 1953.

Scientists like Kurt Benirschke recognized the potential for conservation. In 1972, he founded San Diego's Frozen Zoo, urging colleagues to create genomic libraries. He believed in collecting "things for reasons we don't understand," a concept historian Joanna Radin calls "planned hindsight." The Frozen Zoo now holds over 10,000 tissue samples, including one extinct species.

The potential of these frozen tissues for de-extinction was dramatically confirmed in the new millennium. The Pyrenean ibex (bucardo) was declared extinct in 2000 after the death of its last living member, Celia. However, tissue samples from Celia's ear had been frozen. A team of Spanish, French, and Belgian scientists attempted to clone her. They transferred bucardo DNA into domestic goat eggs, resulting in 208 embryos. Only one pregnancy carried to term, and the cloned bucardo kid was born via C-section. Genetically identical to Celia, the kid appeared healthy but never took a breath, dying within minutes due to a defective lung.

Redefining Extinction

This cloning attempt raises several questions: Was it the world's first "double extinction"? Was it a failed de-extinction because the clone couldn't perform the same ecological function? Or, more provocatively, did the bucardo never truly go extinct?

The International Union for Conservation of Nature (IUCN) declares a species extinct when there is "no reasonable doubt that the last individual has died." However, some de-extinction advocates argue that if an animal's tissues and cultured cells persist in cryopreservation, they are not truly dead or extinct. This perspective, championed by figures like Ben Novak (involved in passenger pigeon de-extinction efforts), suggests that frozen tissues exist in an "evolutionarily torpid" state, making the death of the last living animal merely a pause, not an ending.

This redefinition has profound implications for conservation. If frozen cells forestall extinction, when and how do we declare a species lost? If genetic material assuages guilt, why invest in protecting living species? What distinguishes being alive from existing as dormant genetic material?

The Ethics and Future of De-extinction

De-extinction is often presented as a means of ecological recovery, but it also represents a deliberate effort to build radically different futures. This future-oriented nature is often underestimated, yet it has the potential to reshape our relationship with life and death in the natural world.

Critics worry that if extinction is no longer seen as irreparable harm, threatened species will suffer. The finality of species loss has historically motivated conservation. If species can exist as disembodied genetic lineages in frozen arcs, might we become less compelled to protect living populations? The high, potentially astronomical, cost of de-extinction also raises concerns about diverting resources from traditional conservation efforts.

De-extinction enthusiasts counter that their funding comes from private donors who might not support traditional conservation. However, this highlights the uncomfortable connections between science, capitalism, and philanthropy. The concentration of wealth allows a few individuals to disproportionately influence the future of conservation, raising questions about democratic scrutiny and the origins of such wealth.

Advocates also argue that de-extinction could help re-establish lost ecosystems, such as the hope of bringing back mammoths to transform Siberian tundra into grassland. Furthermore, gene-editing techniques developed for de-extinction could protect threatened species by reintroducing genetic diversity or engineering disease resistance. The recent "return of the direwolf" project, though controversial for its claims of breeding grey wolves engineered to resemble direwolves, demonstrated the potential of synthetic biology for conservation.

In October 2025, the IUCN rejected a moratorium on releasing genetically modified organisms into the wild for conservation, leading to its first policy on synthetic biology. This suggests that engineered organisms released into the wild will be closely monitored on a case-by-case basis, indicating that de-extinction is rapidly moving from possibility to policy.

A Crossroads for Humanity

If de-extinction becomes routine, future generations might view extinction not as a tragedy but as a temporary state. While the desire to move beyond grief to joy and wonder is understandable, accepting that frozen cells forestall extinction fundamentally alters our moral obligation to the living. The question shifts from whether species can be revived to whether we still feel compelled to save them before they die.

Cryopreservation transforms extinction from a permanent loss into a temporary inconvenience. However, the biodiversity crisis requires better relationships with living beings, seeing them as kin and neighbors with their own claims to justice, not just resources to manipulate. De-extinction, in this view, risks becoming the bioengineering of life forms named after lost species to assuage human guilt, rather than a genuine revival.

Relying on preserved genomes risks reducing species to mere genetic information, rather than appreciating them as living ways of being. This genetic determinism is troubling. What is often lost in de-extinction debates is the focus on creating a future where other ways of being thrive as they were meant to, not as humanity dictates. Even if a dodo or passenger pigeon were revived, how would it learn to live as its ancestors? This highlights humanity's sense of unique authority over other species, an entitlement that has underpinned many environmental crises. When technology seemingly fixes mistakes without requiring behavioral change, it delays true justice.

Humanity stands at a crossroads. We have lost many species due to exploitation and face losing more. Hope endures, but it lies not in perpetuating human supremacy, but in recognizing the needs and rights of all life. Instead of reducing life to genomes, we should rethink our relationship with Earth, holding ourselves accountable for losses and transforming our interactions with life.

De-extinction is already happening and will continue, yielding new life forms. Whether this constitutes justice is an open and complex question. The speaker emphasizes the awe of living life, recalling skies teeming with seabirds in Newfoundland. This abundance, often taken for granted and treated as exploitable resources, is at risk. Extinction, while natural, is also a human idea used to make meaning from loss, making it a political choice. Recognizing the deep roots of the present moment is essential for securing justice for all life. By transforming the politics of crisis and exploitation into an ethics of care, we can build futures where extinction is radically reduced because we have recalibrated our relationship with those we share the planet with. Hope, imagination, and refusal are crucial for the sake of all life on Earth.