Buzz
In the early 2000s, a tree tragically crushed the last known Pyrenean ibex, adding another entry to the ever-growing list of extinct animals. Then in 2009, a goat gave birth to a cloned Pyrenean ibex through a government-backed miracle, making history as the first species ever resurrected. However, the joy was short-lived—just seven minutes later, the clone perished, and the Pyrenean ibex was cemented as the only species to have gone extinct twice. Despite this, the potential to bring back other extinct creatures remains, and now we may be on the verge of seeing a whole new wave of animal resurrections.
10. Gastric Brooding Frogs
It’s always tragic when a species vanishes, but it feels even more regretful when it’s something as extraordinary as the gastric brooding frog. This medium-sized Australian frog might not seem too remarkable at first glance, but there was so much we never got the chance to learn. Discovered in 1972, it was declared extinct just over a decade later in 1983. What made the gastric brooding frog so fascinating was its unique reproductive method: It turns its stomach into a womb and gives birth by ‘vomiting’ its offspring. During this process, the frog stops eating, redirects its stomach acid, and its stomach swells so much that its lungs collapse, forcing it to breathe through its skin.
Michael Archer, a zoology professor at the University of New South Wales, is at the forefront of the effort to resurrect the gastric brooding frog. And he’s not just talking about it—he’s making real progress. In 2011, Archer and his team successfully created a cluster of gastric brooding frog cells that began reproducing. While the work is moving forward, it’s not without challenges. The surrogate species they’ve chosen, barred frogs, have the closest DNA match but only reproduce twice a year. If they miss that crucial window, they must wait until the next breeding season for viable eggs.
9. Thylacine
The thylacine, also known as the Tasmanian tiger, was officially declared extinct in 1986, though it hadn’t been seen for 50 years prior. Once a common part of Tasmania's ecosystem, the thylacine became a problem for sheep farmers in the 1800s. In response, the Tasmanian government offered £1 for every thylacine killed, leading to its rapid decline. The last known thylacine died in 1936, marking the sad end of the species.
However, the thylacine wasn’t lost forever. In 1918, Museum Victoria in Melbourne preserved several thylacines in alcohol. With these rare tissue samples from nearly a century ago, two researchers from the University of Melbourne managed to extract enough DNA to reconstruct part of the thylacine genome. By 2008, they had successfully inserted this genome into a mouse embryo, and the mouse began showing traits of an animal that had been gone from the Earth for 80 years.
8. Aurochs
Aurochs, the wild ancestors of today’s European cattle, were declared extinct in 1627 after their natural habitat was gradually overtaken by the expansion of human civilization during the Middle Ages. Though no living aurochs have been seen for nearly 400 years, their genetic lineage remains strong, making them prime candidates for de-extinction efforts.
A Dutch organization called Stichting Taurus is tackling the challenge of resurrecting the aurochs by examining bone fragments to decode their DNA. The plan? To ‘evolve’ a modern cow. Once they have successfully reconstructed the aurochs' DNA, they’ll compare it with living European cattle to identify the closest genetic match. If a suitable match is found, they’ll introduce the aurochs DNA into an embryo, then selectively breed the cattle over several generations. This would effectively reverse centuries of evolution in just a few years, with the goal of reintroducing the aurochs to the Dutch countryside and eventually replacing domesticated cattle.
This isn't the first time someone has tried to clone the aurochs. During World War II, the Nazis made a similar attempt, creating a hybrid strain of cattle known as 'heck cattle.'
7. Dusky Seaside Sparrow
When NASA constructed the Kennedy Space Center on Merritt Island in 1965, they encountered an unexpected problem: the area was infested with mosquitoes. In an effort to deal with the swarms, they flooded the surrounding salt marshes to eliminate the larvae. However, this also destroyed the only habitat of the dusky seaside sparrow, and the species never recovered. The last known individual of the species passed away in captivity in 1987.
The final dusky seaside sparrow, named 'Orange Band,' was given a ceremonial farewell. Before it was laid to rest, its heart and lungs were carefully removed, preserved on ice, and kept with the hope of one day cloning the bird. While there haven't been any cloning attempts yet, scientists have been working on mapping the sparrow’s DNA from the preserved tissue. Once the process is perfected, the dusky seaside sparrow could very well be one of the first species to return.
6. Irish Elk
The biggest challenge in de-extinction today is finding suitable surrogates to give birth to animals that have been extinct for centuries. The current method involves placing the DNA of an extinct species into the embryo of a modern animal with a similar enough genetic makeup to carry the clone to term. However, in the case of prehistoric creatures like the Irish elk, a member of the megacerine family of giant deer, the challenge becomes even greater. How do you find a modern deer that can carry an animal that might grow to a height of two meters (about seven feet) and sport 4.2-meter (14 feet) antlers?
It turns out, the answer might be closer than expected. Researchers at University College London discovered that the closest living relative of the Irish elk is the fallow deer, which is commonly found in both England and Ireland. Now, they’re working on mapping the DNA of a 13,000-year-old Irish elk fossil, with the ambitious goal of bringing this ancient giant back from extinction in the near future.
5. Carolina Parakeet
Parrots and parakeets are typically associated with tropical regions, like Central America. However, less than a century ago, one species of parakeet called the Carolina parakeet made its home along the Eastern coast of the United States. Unfortunately, this bird went extinct in 1918. Like many species lost to history, the Carolina parakeet’s demise was driven by overhunting. The bird’s brightly colored feathers became highly sought after for use in hats and clothing, and by the early 1900s, the species was nearly wiped out in the wild.
Thankfully, dozens of specimens of the Carolina parakeet remain from the time before its extinction, and just last year, mitochondrial DNA was successfully sequenced from eggshell fragments at the New York State Museum. While there aren't any official plans to clone the Carolina parakeet yet, there has been ongoing interest from biologists and historians. The same researchers who sequenced the DNA have even gone so far as to propose that the Nanday parakeet could serve as a potential surrogate for cloning, should the process ever move forward.
4. Huia Bird
The huia bird, a large waterfowl native to New Zealand, was most notable for the long, curved beak found only in females of the species. The Maori people of New Zealand regarded the huia as a sacred animal, often killing them solely for their feathers, which were used to create elaborate ornamental headdresses. When European settlers arrived, they quickly took a liking to these feathered accessories and proceeded to hunt the bird into oblivion. The last confirmed sighting of the huia occurred in 1907. While it’s generally believed to be extinct, there is still a possibility that a few huia may be hiding in the depths of Te Urewera National Park on New Zealand’s North Island.
In 1999, a group of geneticists in New Zealand decided to investigate whether it would be possible to clone a huia and restore the species. After discussing the idea, they agreed it could be done, and a US-based start-up named CyberUni pledged to fund the venture. Even the Maori, who considered the huia a sacred bird, gave their approval for the project. Although progress has yet to be made, the plan is set: all that would be needed is to find a viable cell from one of the few remaining museum specimens, extract its nucleus, implant it into an ovum from another bird, and then stimulate the cell's division using an electric shock or UV radiation. Seems simple enough.
3. Woolly Mammoth
The woolly mammoth is among the most famous candidates for de-extinction—and it may actually become a reality. While no living mammoth has roamed the Earth for around 200,000 years, their remains are exceptionally well-preserved in Siberian permafrost. This frozen environment has allowed scientists to uncover intact specimens, many of which are so well-preserved that they appear almost fresh.
In 2011, a team of researchers from Tokyo set a bold deadline: they would have a living, breathing woolly mammoth within five years. While the cloning process itself is technically feasible—by extracting nuclei from mammoth cells, inserting them into embryos of another species, and implanting them into a surrogate mother—the mammoth cells often die before the nucleus can be extracted, which presents a significant hurdle.
In 2006, a breakthrough was made when scientists discovered that by introducing four simple proteins into an adult cell, it can be reverted back into an embryo stem cell. This method is faster than the traditional nuclear extraction process and offers the advantage of stem cells, which have a much longer lifespan than most other cell types. From stem cells, it becomes possible to create reproductive cells based on sex—sperm from a male mammoth’s cell or gametes from a female. With those two key pieces, the possibilities are endless.
But the key question that looms over all of these efforts is whether a resurrected species would be able to thrive in the wild again. Would it simply survive, or would it dominate and push other species out of their natural habitats? And the most pressing question of all: Where are the dinosaurs?
2. Passenger Pigeon
Once a common sight across the Eastern and Central United States, passenger pigeons were incredibly abundant—so much so that entire flocks could number in the millions. But their tragic fate was sealed by their popularity as a food source and their vulnerability to hunters. Despite efforts to conserve the species in the early 1900s, their numbers dwindled too far, too quickly, and soon there weren’t enough left to sustain a viable population.
A team at the University of California is currently working on a project to resurrect the passenger pigeon using DNA extracted from Martha, the last known passenger pigeon who died in 1914. At present, passenger pigeons are considered the most viable candidate for de-extinction. This is because we have well-preserved DNA samples and there are closely related species, such as the band-tailed pigeon, that could serve as surrogates. The project's focus now is to compare the DNA of the passenger pigeon with that of the band-tailed pigeon, with hopes that a female band-tailed pigeon could soon lay an egg containing a passenger pigeon.
1. Steller’s Sea Cow
The Steller’s sea cow, a distant relative of the manatee, was first discovered in 1741 off the coast of Bering Island near Russia. Large, slow-moving, and an unexpectedly poor swimmer, the Steller’s sea cow had already seen its population shrink significantly by the time it was discovered, with the species confined to just a small section of the Bering Sea. Sailors and fur traders, who found them easy to hunt, quickly wiped out the remaining population, and by 1768—just 27 years after its discovery—the Steller’s sea cow was officially declared extinct.
Although no Steller’s sea cows have been seen for almost 250 years, their bones continue to wash up on beaches. In 2011, a team of Russian researchers managed to sequence DNA from several of these specimens, creating the potential for a cloning project to revive the species.
