De-extinction, or the process of bringing extinct species back to life, is no longer the stuff of science fiction. Thanks to advances in genetic science, the possibility of reviving extinct species is now possible.
Below, we examine the de-extinction process and reveal 10 species that are realistic candidates for de-extinction.
How Does De-Extinction Work?
De-extinction works through the use of two primary technologies: cloning and gene editing.
Cloning involves extracting DNA from preserved remains of an extinct species, such as fossils or museum specimens, and inserting it into the egg cells of a closely related species. This modified embryo is then implanted into a surrogate mother, which gives birth to an organism genetically identical to the extinct species.
Gene editing, on the other hand, uses techniques like CRISPR (short for “clustered regularly interspaced short palindromic repeats”) to alter the DNA of a living species by introducing genes from an extinct species. This creates a hybrid organism that expresses traits of the extinct species, rather than fully cloning it. While cloning aims to recreate the extinct species in its entirety, gene editing can bring back specific traits by modifying the genome of a living relative.
What is Needed for De-Extinction?
For de-extinction to succeed, several factors must be in place:
1. DNA Quality and Availability
The availability of high-quality, well-preserved DNA is crucial. Species that went extinct relatively recently are more likely to have recoverable DNA, making them better candidates for revival.
2. Close Living Relatives
Cloning or gene editing often relies on the existence of a close living relative. Having a close living species is essential for gene editing and cloning.
3. Ecological Feasibility
Introducing an extinct species into a modern ecosystem must be carefully considered. The species must fit into its environment without disrupting the balance of current species or habitats.
4. Ethical Considerations
The process of de-extinction raises ethical concerns about animal welfare. Questions about the quality of life for revived species and the potential consequences for modern wildlife need to be addressed.
5. Technological Advancements
Advances in gene editing and cloning are essential for de-extinction efforts. The ability to accurately edit the DNA of living species and reintroduce extinct traits is a key factor in the success of these projects.
Companies like Colossal Biosciences and Revive & Restore, are leading the charge on de-extinction projects. While the science behind de-extinction is still in its infancy, these efforts offer exciting potential for restoring lost biodiversity and rebalancing ecosystems.
10 Extinct Animals We Could Bring Back
1. Dire Wolf
The dire wolf (Canis dirus), a large carnivorous species that went extinct more than 10,000 years ago, is the first animal to have been successfully “resurrected.” Colossal Biosciences, a leading company in the field, claims to have “de-extincted” the dire wolf using gene editing technology in 2024.
Using extracted DNA from dire wolf fossils, including a tooth and a skull, the species’ genome was reconstructed. They identified key genes responsible for the dire wolf’s size, musculature, coat color, and hair length. Using CRISPR technology, Colossal Biosciences edited the genomes of grey wolves, introducing these dire wolf traits. The edited embryos were implanted into surrogate dog mothers, resulting in three puppies—Romulus, Remus, and Khaleesi—genetically modified grey wolves with dire wolf traits.
2. Passenger Pigeon
The passenger pigeon, once the most abundant bird in North America, went extinct in the early 20th century due to hunting and habitat destruction. The possibility of bringing back the passenger pigeon is being explored by scientists using the DNA of preserved specimens and the closely related band-tailed pigeon as a genetic base. Revive & Restore’s goal is to hatch the first generation of new passenger pigeons in 2025 and begin trial releases into the wild thereafter. Successful de-extinction would restore an important ecological role related to seed dispersal in forest ecosystems.
3. Woolly Mammoth
The woolly mammoth is one of the most famous candidates for de-extinction, and progress is being made to bring this iconic Ice Age species back. Scientists, particularly those at Colossal Biosciences, are working on editing the DNA of modern elephants to introduce woolly mammoth genes, creating a hybrid species. Colossal Biosciences says that the woolly mammoth is its landmark de-extinction project is to produce “a cold-resistant elephant with all of the core biological traits of the woolly mammoth. It will walk like a woolly mammoth, look like one, sound like one, but most importantly it will be able to inhabit the same ecosystem previously abandoned by the Mammoth’s extinction.” They expect to produce the first “mammoth” calves by 2028.
4. Heath Hen
The heath hen, a type of grouse that once inhabited the northeastern United States, was driven to extinction in the early 20th century. Efforts to revive the heath hen are still in their early stages, relying on DNA from museum specimens and the closely related greater prairie chicken. Reviving the heath hen could help restore grassland ecosystems, although its natural habitat has been significantly altered by human development.
5. Quagga
The quagga, a subspecies of zebra with a unique coat pattern, went extinct in the late 19th century due to overhunting. While full cloning has not occurred, scientists have made progress by selectively breeding plains zebras to resemble the quagga. These efforts have produced animals that visually resemble the extinct quagga, and they could play a role in restoring biodiversity to South Africa’s grassland ecosystems.
6. Thylacine
The thylacine, also known as the Tasmanian tiger, was a carnivorous marsupial that went extinct in the 1930s due to hunting and habitat destruction. Geneticists are working on extracting DNA from preserved thylacines and using gene editing technologies to potentially revive the species. The Tasmanian tiger is one of the species that Colossal Biosciences is targeting for de-extinction. However, the feasibility of reintroducing the thylacine into modern Tasmania’s ecosystems is still under consideration, as its role as an apex predator would need careful management.
7. Dodo Bird
The dodo, an iconic flightless bird, was driven to extinction in the late 17th century by hunting and the introduction of invasive species. Though a full revival is still a distant goal, scientists are working to sequence the dodo’s genome using preserved DNA. Colossal Biosciences says it is committed to bringing back the dodo. However, the ecological feasibility of reintroducing the dodo into its native environment is highly questionable, as the island ecosystem that once supported it no longer exists in the same form.
8. Aurochs
The aurochs, the wild ancestor of domestic cattle, went extinct in the 1600s. Instead of cloning the aurochs, scientists are selectively breeding modern cattle to recreate traits of the aurochs, a process known as back-breeding. Aurochs differed significantly from modern cattle in terms of size, physical characteristics, and behavior. They were much larger, standing up to 6 feet (1.8 meters) at the shoulder, had more powerful horns, thicker coats, and were more muscular. The dutch-based Tauros Programme’s goal is to rewild a bovine capable of fulfilling the ecological role once held by the aurochs in European ecosystems.
9. Steppe Bison
The steppe bison was a dominant species in the plains of North America and Eurasia but went extinct around 10,000 years ago. Scientists are working on reviving this species using DNA from preserved remains and by breeding modern bison with traits from the steppe bison. If successful, the steppe bison could help restore biodiversity and ecosystem health in grassland regions.
10. Great Auk
The great auk, a flightless seabird that went extinct in the mid-1800s, is another potential candidate for de-extinction. While its DNA is well-preserved in museum specimens, reviving the great auk faces significant challenges, including finding a suitable living relative for genetic material. The ecological impact of reintroducing a flightless seabird to modern coastal ecosystems would also need careful assessment.
Could Dinosaurs Be Brought Back From Extinction?
Bringing back dinosaurs isn’t feasible with current technology, and it’s unlikely to happen any time soon. Jurassic Park will have to wait. Despite the appeal of the idea, there are several significant hurdles that make it impossible right now.
First, dinosaur DNA has long since degraded. The oldest DNA ever recovered is about 1 million years old, while dinosaurs went extinct around 65 million years ago. Even if we found some DNA fragments, they’d be incomplete and too degraded to reconstruct a full genome, which is essential for cloning.
Second, there are no closely related species available for cloning. While birds are considered distant relatives of dinosaurs, the gap is too large for cloning to work effectively. Without a modern species that’s genetically close enough to provide the necessary cells and egg, the process becomes unfeasible.
Finally, even if somehow we could recreate dinosaurs, the environmental challenges would be massive. Dinosaurs lived in ecosystems that no longer exist, and today’s atmosphere, climate, and food sources are vastly different. The consequences of reintroducing such animals would likely be unpredictable and potentially disastrous.
While scientists are advancing in the area of de-extinction for more recently extinct species like the woolly mammoth, dinosaurs are a different story. The revival of these ancient creatures is firmly in the realm of science fiction, not reality.
