10 Extinct Animals That Could Come Back Through Science
Extinction used to be forever. But advances in genetic engineering, cloning, and DNA editing are making possible what once seemed like science fiction: bringing extinct species back to life. This field, called de-extinction, already has real projects underway.
Meet 10 extinct animals that scientists are trying to resurrect and how this could change the world.
1. Woolly Mammoth (Mammuthus primigenius)
Extinct for: ~4,000 years (last specimens on Wrangel Island)
The woolly mammoth is the number one candidate for de-extinction. The company Colossal Biosciences, founded in 2021, has received more than $225 million in investments to bring the mammoth back.
How It Would Be Done
Scientists plan to use CRISPR technology to insert mammoth genes into the DNA of Asian elephants, their closest living relatives. The selected genes are responsible for characteristics like long hair, small ears, and an extra layer of fat.
Why Bring the Mammoth Back?
Beyond scientific fascination, there are ecological reasons. Mammoths helped maintain Arctic grasslands by trampling snow and allowing cold air to freeze the soil. Without them, permafrost is melting faster, releasing methane and accelerating global warming.
Forecast
Colossal plans to have the first "mammoth" (actually an elephant with mammoth characteristics) by 2028.
2. Dodo (Raphus cucullatus)
Extinct for: ~350 years (last sighting in 1681)
The dodo, a flightless bird native to Mauritius, is the universal symbol of extinction. The same company Colossal announced in 2023 a project to resurrect it.
The Challenge
Dodo DNA was sequenced from museum specimens. Scientists plan to use the Nicobar pigeon, the closest living relative, as a genetic base. The process involves editing the pigeon's genome to add dodo characteristics.
Obstacles
The dodo was a large, flightless bird, very different from any living pigeon. Recreating its size, beak, and behavior will be extremely complex. Additionally, the Mauritius ecosystem has changed drastically since its extinction.
3. Thylacine (Thylacinus cynocephalus)
Extinct for: ~90 years (last specimen died in 1936)
The thylacine, or Tasmanian tiger, was the largest carnivorous marsupial of modern times. Its extinction was caused by intensive hunting and habitat destruction in Australia and Tasmania.
Resurrection Project
The University of Melbourne, in partnership with Colossal, announced in 2022 a $5 million project to bring the thylacine back. Well-preserved DNA was extracted from museum specimens.
Viability
The thylacine is considered one of the most viable candidates for de-extinction because it went extinct recently, has well-preserved DNA, and its closest living relative (the numbat) still exists. Scientists estimate they could have a thylacine pup in 10–15 years.
4. Passenger Pigeon (Ectopistes migratorius)
Extinct for: ~110 years (last specimen, Martha, died in 1914)
The passenger pigeon was the most abundant bird in North America, with populations estimated at 3 to 5 billion individuals. Flocks so large they darkened the sky for hours were hunted to extinction in less than 50 years.
Revive & Restore Project
The organization Revive & Restore has been working since 2012 to bring the passenger pigeon back. The plan involves editing the genome of the band-tailed pigeon, the closest relative, to recreate passenger pigeon characteristics.
Ecological Impact
The passenger pigeon played a crucial role in North American forests, dispersing seeds and creating clearings that promoted plant diversity. Its extinction permanently altered the continent's forest ecosystems.
5. Northern White Rhinoceros (Ceratotherium simum cottoni)
Functionally extinct: only 2 living females remain (Najin and Fatu)
Technically not extinct, but with only two surviving females and no males, the subspecies is doomed without scientific intervention.
In Vitro Fertilization
Scientists collected eggs from Najin and Fatu and fertilized them with frozen sperm from deceased males. Viable embryos were created and are stored, awaiting transfer to a surrogate mother (a female southern white rhinoceros).
Stem Cells
A more ambitious approach involves creating sperm and eggs from stem cells of northern white rhinos preserved in genetic banks. This would drastically increase the genetic diversity of the restored population.
6. Pyrenean Ibex (Capra pyrenaica pyrenaica)
Extinct for: ~26 years (last specimen died in 2000)
The bucardo, a subspecies of Pyrenean mountain goat, has the distinction of being the only animal that was "de-extincted" and then went extinct again.
The 2003 Attempt
In 2003, Spanish scientists cloned a bucardo using preserved DNA from the last specimen. The offspring was born alive but died after 7 minutes due to a lung defect. It was the first time an extinct animal was brought back to life, even if briefly.
New Attempts
With advances in cloning technology since 2003, scientists believe a new attempt would have much greater chances of success. Tissue samples from the last bucardo are still preserved.
7. Aurochs (Bos primigenius)
Extinct for: ~400 years (last specimen died in 1627)
The aurochs was the wild ancestor of domestic cattle. It was an imposing animal, up to 1.80 meters tall with enormous horns. It was hunted to extinction in Europe.
Taurus Project
The Taurus Project, started in 2008, uses selective breeding of cattle breeds that still carry aurochs genes to "reverse" domestication. Breeds like Sayaguesa, Highland, and Maremmana are crossed to produce animals increasingly similar to aurochs.
Results
After several generations, Taurus Project animals already significantly resemble aurochs in size, horn shape, and coloration. Although not genetically identical, they are functionally similar and could play the same ecological role.
8. Moa (Dinornis robustus)
Extinct for: ~600 years
Moas were giant flightless birds native to New Zealand. The largest species reached 3.6 meters in height. They were hunted to extinction by the Maori after their arrival in New Zealand.
Preserved DNA
Moa DNA was successfully extracted from preserved bones and feathers. The complete genome was sequenced, providing a detailed genetic map. The closest living relative is the tinamou, a South American bird.
Challenges
The size difference between the tinamou (chicken-sized) and the moa (3.6 meters) makes de-extinction extremely challenging. It would require modifying thousands of genes related to growth.
9. Quagga (Equus quagga quagga)
Extinct for: ~140 years (last specimen died in 1883)
The quagga was a zebra subspecies with stripes only on the front half of its body. Native to South Africa, it was hunted to extinction by European colonizers.
Quagga Project
Since 1987, the Quagga Project in South Africa has used selective breeding of plains zebras with fewer stripes to recreate the quagga's appearance. After several generations, the animals already remarkably resemble historical quaggas.
Partial Success
Although the project animals are not genetically identical to original quaggas, they are visually very similar. Some scientists argue that, since the quagga was a subspecies of the plains zebra, selective breeding can effectively "recreate" the quagga.
10. Japanese Wolf (Canis lupus hodophilax)
Extinct for: ~120 years (last confirmed sighting in 1905)
The Honshu wolf was the smallest wolf in the world, native to Japan. It was hunted to extinction by farmers and fell victim to rabies epidemics introduced by domestic dogs.
Possibility of Resurrection
Preserved specimens in Japanese museums contain usable DNA. The gray wolf, a close relative, could serve as a genetic base. However, there are no active de-extinction projects for this species at the moment.
Cultural Importance
The Honshu wolf was revered in Japanese culture as a protector of crops and messenger of the gods. Shrines dedicated to the wolf still exist in Japan, and unconfirmed sightings are reported regularly.
The Ethical Challenges of De-Extinction
Bringing extinct animals back raises profound questions. Where would these animals live, considering that their original habitats may no longer exist? Wouldn't the resources spent on de-extinction be better applied to protecting endangered species that still exist?
Furthermore, a "de-extincted" animal wouldn't be exactly the original species, but a genetic approximation. Without the culture and learned behaviors of their ancestors, these animals could struggle to survive.
On the other hand, advocates argue that de-extinction can restore damaged ecosystems, generate valuable scientific knowledge, and inspire greater interest in conservation.
CRISPR Technology: The Tool of De-Extinction
Most de-extinction projects depend on CRISPR-Cas9 technology, a genetic editing tool that works like "molecular scissors." Developed in 2012 by Jennifer Doudna and Emmanuelle Charpentier (Nobel Prize in Chemistry 2020), CRISPR allows cutting and inserting DNA sequences with unprecedented precision.
In the context of de-extinction, the process works like this: scientists sequence the extinct animal's DNA from preserved remains. They compare that genome with the DNA of the closest living relative and identify key differences. Using CRISPR, they insert the extinct species' genes into the living species' genome — creating a hybrid that carries characteristics of the extinct animal.
Geneticist George Church's laboratory at Harvard is the nerve center of the mammoth project. His team has already identified 44 genes responsible for cold adaptations — long hair, smaller ears, hemoglobin tolerant to low temperatures, and extra subcutaneous fat. The plan involves inserting these genes into Asian elephant cells, creating an edited embryo, and gestating it in an artificial womb (since no elephant should be forced to carry an experimental embryo).
The challenge: large animals like mammoths have enormous genomes (~4.7 billion base pairs). Editing thousands of genes simultaneously without causing problems is technically challenging. Additionally, the genome isn't everything — epigenetic factors (gene expression), microbiome, and learned behavior cannot be recreated with DNA alone.
The Conservation Debate
The conservation community is divided. Biologist Stuart Brand (co-founder of Revive & Restore) argues that de-extinction is a legitimate conservation tool — restoring keystone species can regenerate entire ecosystems. Meanwhile, biologist Beth Shapiro (author of "How to Clone a Mammoth") warns that money spent on de-extinction could save dozens of currently endangered species. The IUCN (International Union for Conservation of Nature) published guidelines in 2016 recognizing the potential of de-extinction but calling for caution and prioritization of living species at risk.
Project Comparison
| Animal | Extinct for | Investment | Viability | Forecast |
|---|---|---|---|---|
| Woolly Mammoth | ~4,000 years | $225M+ | High | 2028 |
| Dodo | ~350 years | $150M | Medium | 2030+ |
| Thylacine | ~90 years | $5M+ | High | 2033–2038 |
| Passenger Pigeon | ~110 years | $10M+ | Medium | 2030+ |
| Northern White Rhino | Functional | $20M+ | High | 2026–2028 |
| Pyrenean Ibex | ~26 years | $2M | High | 2025–2027 |
Conservation and the Future of Wildlife
Wildlife conservation is one of the greatest challenges of the 21st century. Habitat loss, climate change, illegal hunting, and pollution are threatening species across the planet at an alarming rate. Scientists estimate that we are living through the sixth mass extinction in Earth's history, with species disappearing at a rate one thousand times greater than the natural background rate.
However, there are reasons for optimism. Successful conservation programs have managed to save species from the brink of extinction. The Iberian lynx, European bison, and American bald eagle are examples of species that have recovered thanks to dedicated conservation efforts. Protected areas, ecological corridors, and captive breeding programs are making a real difference in preserving biodiversity.
Technology is also playing a crucial role in conservation. Drones monitor wild animal populations, cameras with artificial intelligence automatically identify species, and GPS trackers allow researchers to follow animal movements in real time. These tools provide essential data for evidence-based conservation decisions that can protect vulnerable ecosystems.
Surprising Curiosities and Adaptations
The animal kingdom is an inexhaustible source of surprises and wonders. Each species has developed unique adaptations over millions of years of evolution, resulting in a diversity of forms, behaviors, and survival strategies that defy imagination. From microscopic organisms inhabiting the ocean depths to majestic eagles soaring over mountains, every creature has a fascinating story to tell.
Animal communication is far more complex than we once imagined. Whales sing melodies that travel hundreds of kilometers, elephants communicate through ground vibrations, and bees dance to indicate the location of food sources. Recent research suggests that many species possess forms of language far more sophisticated than scientists previously believed possible.
Animal intelligence also continues to surprise researchers. Crows manufacture tools, octopuses solve complex puzzles, dolphins recognize themselves in mirrors, and chimpanzees demonstrate empathy and cooperation. These discoveries are redefining our understanding of consciousness and cognition in the animal kingdom and challenging the boundaries we once drew between human and animal minds.
The Relationship Between Humans and Animals Throughout History
The relationship between humans and animals is one of the oldest and most complex in the history of civilization. From the domestication of the first dogs more than 15,000 years ago to modern animal-assisted therapy programs, this partnership has been fundamental to human development. Animals have served as companions, work tools, food sources, and even religious symbols in different cultures throughout history.
Science is revealing that the benefits of living with animals go far beyond companionship. Studies show that having a pet can reduce blood pressure, decrease stress, combat depression, and even strengthen the immune system. Therapy programs with horses, dolphins, and dogs are helping people with autism, PTSD, and other conditions improve their quality of life in measurable and meaningful ways.
The debate about animal rights has gained strength in recent decades, leading to significant changes in legislation around the world. The ban on animal testing for cosmetics, the end of practices like bullfighting in several countries, and the creation of sanctuaries for rescued animals reflect a growing awareness about animal welfare and our ethical duty toward other species.
Ecosystems and the Web of Life
Each ecosystem is a complex network of interactions between living organisms and their environment. The removal of a single species can trigger cascading effects that affect the entire system, demonstrating the fundamental interconnection of all life on Earth. The concept of keystone species illustrates how some organisms play disproportionately important roles in maintaining ecological balance.
The oceans, which cover more than 70% of Earth's surface, harbor ecosystems of extraordinary complexity. Coral reefs, known as the tropical forests of the sea, support about 25% of all marine life despite occupying less than 1% of the ocean floor. Ocean acidification and rising water temperatures are threatening these vital ecosystems, with potentially catastrophic consequences for marine biodiversity.
Tropical forests, especially the Amazon, play a crucial role in regulating the global climate. In addition to absorbing large amounts of carbon, these forests generate rainfall that irrigates entire regions and harbor incomparable biodiversity. Protecting these ecosystems is not just an environmental issue but a necessity for the survival of humanity itself in the coming decades.
Frequently Asked Questions
Is it possible to bring back dinosaurs like in Jurassic Park?
Not with current technology. DNA degrades completely after about 6.8 million years, and dinosaurs went extinct 66 million years ago. No dinosaur DNA has been preserved anywhere.
How much does a de-extinction project cost?
Projects like the mammoth cost hundreds of millions of dollars. Colossal Biosciences has already raised more than $225 million. Smaller projects, like the bucardo, cost a few million.
Would de-extincted animals be identical to the originals?
Not exactly. They would be genetic hybrids with characteristics of the extinct species inserted into the genome of a living relative. Learned behaviors and social culture cannot be recovered.
Can de-extinction help the environment?
Potentially yes. Mammoths could help preserve Arctic permafrost. Passenger pigeons could restore forest ecosystems. But the actual impacts are difficult to predict.
Is de-extinction legal?
Currently, there is no specific legislation on de-extinction in most countries. The resulting animal would be classified as a genetically modified organism (GMO), subject to existing regulations for transgenics — which vary enormously between countries.
Sources: Colossal Biosciences, Revive & Restore, Nature, Science, IUCN. Updated January 2026.
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