Extinct Animals That Scientists Aim to Resurrect
From mammoths to dodos, explore the species scientists hope to bring back with cutting-edge genetics.
Advances in genetics and biotechnology have made it possible to envision what was once science fiction: bringing extinct species back to life. Whether to right historical wrongs, restore lost ecosystems, or simply demonstrate the power of science, the notion of de-extinction—or resurrection biology—is both thrilling and controversial. This article explores the species that may walk the Earth again, the science behind their potential return, and the debates surrounding their resurrection.
What Is De-Extinction?
De-extinction is the process of reviving extinct species using biotechnology, genetics, and selective breeding. Although true revival is technologically daunting, especially for species lost decades or centuries ago, scientists are developing methods to recreate or closely mimic these lost animals by:
- Recovering and sequencing ancient DNA from fossils, preserved remains, or museum specimens
- Editing the genomes of closely related living species to introduce key extinct traits
- Cloning or breeding animals that resemble extinct counterparts through carefully managed selective programs
The field is guided by both technological possibility and deep existential, ecological, and ethical questions.
Why Bring Back Extinct Animals?
The idea of resurrecting extinct animals captivates the imagination and highlights several motivations:
- Restoring Lost Ecosystems: Some species, like the woolly mammoth or passenger pigeon, played key roles in shaping landscapes and supporting biodiversity.
- Correcting Human Impacts: Many recently extinct species disappeared due to hunting, habitat destruction, or invasive species caused by humans. Resurrection could be seen as righting a historical wrong.
- Driving Innovation: Attempting to revive lost species pushes the limits of genetic engineering, offering new tools for conservation biology.
- Educational and Cultural Value: The process generates excitement and publicity, potentially inspiring new generations of scientists and conservationists.
Notable Extinct Species Targeted for Resurrection
Among the dozens of candidates, several extinct animals are frequently mentioned in scientific literature and media as possible revival prospects. Below is a detailed look at species at the forefront of de-extinction efforts.
1. Woolly Mammoth (Mammuthus primigenius)
The woolly mammoth, a giant of the last Ice Age, roamed across northern Eurasia and North America, shaping ecosystems known as steppe-tundra. The last population vanished from Wrangel Island around 4,000 years ago.
- Why revive? Mammoths might help restore grasslands, sequester carbon, and combat tundra thaw by trampling moss and crushing trees.
- Scientific approach: Scientists are pursuing two main strategies:
- Editing the genome of the Asian elephant (their closest living relative) to incorporate mammoth genes for traits like thick hair and cold adaptation.
- Cloning using cells or tissue—currently unfeasible due to DNA degradation—but new advances in gene editing and somatic cell nuclear transfer (SCNT) offer hope.
- Status: Teams such as those at Harvard and startups like Colossal have progressed to creating mammoth-like embryos, but it may take many years before calves are born and can survive in the wild.
2. Passenger Pigeon (Ectopistes migratorius)
Once numbering in the billions, the passenger pigeon vanished in the early 20th century due to rampant hunting and habitat destruction. The last individual, Martha, died in 1914.
- Why revive? Passenger pigeons were ecological architects. Large flocks created forest disturbances that shaped plant and animal communities in North America.
- Scientific approach: Since traditional cloning is not viable due to degraded genomes, scientists work to identify genes unique to the passenger pigeon and edit them into the genome of the band-tailed pigeon. The outcome would not be a perfect genetic copy but a living bird genetically and phenotypically similar to its extinct ancestor.
- Status: Projects by Revive & Restore and collaborators are progressing, but full de-extinction for wild release is at least a decade away, with captive breeding targets set for the early 2030s.
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3. Dodo (Raphus cucullatus)
The dodo, an iconic symbol of extinction, disappeared from Mauritius in the late 17th century after humans and introduced animals destroyed its habitat and preyed upon it.
- Why revive? The dodo’s absence had profound effects on Mauritius’ ecosystem. Its return could provide insights into island ecology and the impact of human colonization.
- Scientific approach: Although dodo DNA has been recovered, its closest living relative, the Nicobar pigeon, is still genomically distant. Gene editing and advanced reproductive techniques would be required to bridge the evolutionary gap.
- Status: Sequencing of dodo DNA has advanced, but creating a living dodo remains a long-term ambition pending further breakthroughs in avian genetics.
4. Pyrenean Ibex (Bucardo, Capra pyrenaica pyrenaica)
This mountain goat, native to the Pyrenees, was declared extinct in 2000. In 2003, scientists successfully cloned a female from preserved nuclei; the clone died soon after birth, making it the first (albeit brief) instance of ‘de-extinction.’
- Why revive? The Pyrenean ibex’s demise was largely due to overhunting. Restoring the species could support native biodiversity and test the limits of cloning techniques.
- Scientific approach: Cloning with preserved nuclei and surrogate mothers from closely related species.
- Status: While the cloning technique worked, the short lifespan highlighted developmental hurdles. Efforts continue to refine the process.
5. Thylacine (Tasmanian Tiger, Thylacinus cynocephalus)
The thylacine, a carnivorous marsupial, disappeared from mainland Australia around 2,000 years ago and from Tasmania by the 1930s, mainly due to hunting and habitat loss.
- Why revive? Its extinction drastically shifted Tasmanian ecosystems, with reverberations still felt today.
- Scientific approach: Advances in marsupial genetics offer new hope, utilizing DNA from well-preserved museum specimens and identifying traits to edit into the Tasmanian devil genome.
- Status: The thylacine genome has been sequenced, but significant technological and ethical barriers remain to birthing a live animal.
6. Quagga (Equus quagga quagga)
A subspecies of plains zebra with unique striping, the quagga was hunted to extinction by the late 19th century.
- Why revive? Quaggas shaped South African grasslands, and their revival represents an opportunity to undo human missteps.
- Scientific approach: The Quagga Project uses selective breeding, mating zebras with quagga-like traits to re-create animals visually similar to quaggas over several generations.
- Status: Six “Rau quaggas” already closely resemble the extinct form. These are not genetically identical to original quaggas, but functionally serve many ecological roles of their extinct counterparts.
7. Aurochs (Bos primigenius)
The mighty aurochs, progenitor of modern cattle, once roamed widely through Europe, Asia, and North Africa. The last died in Poland in 1627.
- Why revive? Aurochs played a crucial role in shaping forests and meadows through grazing and trampling. Their return could restore ecological balance in areas now dominated by human-managed livestock.
- Scientific approach: “Back-breeding” programs, using cattle breeds that still retain aurochs traits, aim to recreate the robust appearance and behavior of the original aurochs.
- Status: Some modern cattle closely resemble aurochs, but achieving true genetic and behavioral matches is ongoing.
8. Gastric-Brooding Frog (Rheobatrachus silus)
This unique Australian frog, extinct since the 1980s, gave birth through its stomach—a reproductive strategy never seen elsewhere among vertebrates.
- Why revive? Its distinctive biology makes it both an ecological novelty and a potential source for breakthroughs in medical research, particularly related to tissue regeneration.
- Scientific approach: Scientists at the University of New South Wales have attempted to clone the frog using the “Lazarus project,” implanting extinct frog nuclei into donor eggs from related species.
- Status: Partial success has been achieved, with living embryos created but not yet brought to full development.
The Science and Ethics of De-Extinction
Reviving extinct animals is fraught with practical challenges and philosophical dilemmas.
- Genetic Challenges: Ancient DNA is often fragmented; recreating a viable genome can require filling informational gaps with related species’ DNA.
- Surrogates and Environment: Even with a complete genome, producing a live animal requires a compatible surrogate and a suitable, secure habitat for eventual release.
- Ethical and Ecological Concerns: Critics caution that de-extinction could divert resources from saving endangered species, or introduce unpredictable disruptions to modern ecosystems.
- Conservation Value: Many experts argue resources should first be used to prevent further extinctions and restore wild habitats.
Table: Key Extinct Species Targeted for De-Extinction
| Species | Extinction Date | Main Method | Current Status |
|---|---|---|---|
| Woolly Mammoth | ~4,000 years ago | Genome editing (Asian elephant) | Embryo creation in progress |
| Passenger Pigeon | 1914 | Genome editing (band-tailed pigeon) | Gene editing ongoing |
| Dodo | Late 1600s | Genome sequencing, cloning (future) | DNA sequenced, functional cloning out of reach |
| Quagga | 1883 | Selective breeding | “Rau quaggas” already living |
| Thylacine | 1936 | Genome editing, cloning (marsupials) | Genome sequenced, no live animals |
| Gastric-Brooding Frog | 1980s | Cloning | Embryos created, not viable |
Potential Benefits of De-Extinction
- Ecological restoration: Reintroducing keystone species could rejuvenate habitats and increase biodiversity.
- Scientific discovery: Studying resurrected animals could yield insights into evolution, adaptation, and gene function.
- Conservation tools: Technologies developed in de-extinction projects can help save threatened and endangered living species.
What Challenges Lie Ahead?
- Genomic Gaps: DNA from long-extinct species is incomplete and may require reconstruction using related species.
- Genetics vs. Behavior: Even with genetic similarity, resurrected species may lack key learned behaviors or environmental cues of their ancestors.
- Legal and Regulatory Obstacles: Reintroducing now-extinct animals may conflict with modern laws and land use.
- Ecosystem Integration: Modern ecosystems have changed, and it’s unclear how revived species will fit in or what unintended consequences they may trigger.
Debate: Should We Bring Back Extinct Species?
Opinions about de-extinction are divided among scientists, conservationists, and the public.
- Arguments in Favor:
- Restores ecological balance and lost genetic diversity
- Educational and scientific value
- Can inspire stronger conservation efforts for endangered species
- Arguments Against:
- High costs may divert resources from urgent conservation needs
- Risk of suffering for experimental animals
- Potential for disrupting current ecosystems
- Uncertain success and long-term sustainability
Frequently Asked Questions (FAQs)
What is the main method of bringing back extinct animals?
The primary methods are genome editing using a closely related living species, cloning (where DNA quality permits), and selective breeding to re-create animals phenotypically similar to extinct forms.
Is it possible to truly recreate an extinct animal?
Perfect genetic resurrection is currently unattainable for most species due to incomplete DNA and information loss. However, scientists can create hybrid animals or close proxies that fulfill similar ecological roles.
What species are closest to being revived?
The quagga (via selective breeding) and some species of frogs and pigeons (through genome editing and cloning) are closest to reappearing in the wild, while projects for woolly mammoth are the most advanced among mammals.
Are there risks to de-extinction?
Yes. Risks include unforeseen ecological disruptions, ethical debates about animal welfare, and the possibility that exceeding focus on de-extinction could detract from efforts to save threatened living species.
Could extinct humans like Neanderthals be revived?
Technically conceivable but ethically fraught, the idea of resurrecting extinct human relatives—such as Neanderthals—remains in the realm of scientific speculation and philosophical debate.
Conclusion: The Future of De-Extinction
While the dream of resurrecting extinct animals fuels remarkable scientific innovation, the challenges—genetic, ecological, and ethical—are immense. Yet, each attempt advances our understanding of genetics and conservation. The hope is that, whether or not species like the woolly mammoth ever roam again, the tools developed may help protect the living diversity of our planet for future generations.
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