Can a lost species become un-extinct? In the 1993 film "Jurassic Park," dinosaurs are cloned back to life after their DNA is found intact within the bellies of ancient mosquitoes preserved in amber. While the science of cloning is still in its infancy, many scientists believe it's only a matter of time before extinct animals again walk the Earth. To successfully clone an extinct animal, scientists need to find animal DNA that is almost entirely intact. Some species have substantial potential as candidates because of the availability of what is called ancient DNA, or genetic material from fossils or artifacts. For instance, recently extinct animals, museum specimens, and species preserved in permafrost during the last Ice Age provide ancient DNA. That leaves tackling whether undertaking revivifying or resurrecting an extinct species is sensible, ethical, safe, and affordable. Because of the sheer amount of time that has passed, dinosaurs make unlikely candidates. A real-life Jurassic Park is probably best reserved for the imagination, but a real-life Pleistocene Park? Well, that's another story. Here's our list of 14 extinct animals considered for de-extinction through cloning.

1 of 14 Woolly Mammoth Mauricio Antón / Wikimedia Commons / CC BY 2.5 Wooly mammoths seem like an excellent choice for de-extinction. Many wooly mammoth specimens remain in the permafrost of Siberia. Paleogeneticists, scientists that study preserved genetic material, have sequenced the wooly mammoth genome. The research into the genome, as well as preserved genetic material, has led to work around either creating a wooly mammoth through cloning or through editing the genome of the closest living relative, the Asian elephant. In a "first step" toward resurrecting the mammoth, researchers from Russia and South Korea are working to bring back another extinct animal, the Lena horse, using cells from a 40,000-year-old foal found in Siberia. Despite all the enthusiasm some scientists and many non-scientists have for de-extinction of this species, ethical concerns exist. Wooly mammoths were social animals that lived in herds. Attempts at bringing wooly mammoths back from extinction may fail many times before a viable mammoth is born. If using an Asian elephant as a surrogate carrier of the mammoth, the 22-month gestational period, based on elephant gestation periods, removes the possibility of the elephant carrying an offspring to continue the endangered elephant species. Success in creating a wooly mammoth leaves the problem of what sort of life awaits the animal--lab animal, zoo animal, or resident of Pleistocene Park, an attempt at restoring a steppe ecosystem in Russia.

2 of 14 Tasmanian Tiger Baker; E.J. Keller / Wikimedia Commons / Public Domain The Tasmanian tiger, or thylacine, was a remarkable animal native to Australia and the largest known carnivorous marsupial of modern times. The animals went extinct as recently as the 1930s, mainly due to climate change, bounty hunting, and lack of genetic diversity. Because they went extinct so recently, specimens of the animal remain intact, preserved in collection jars. Some taxidermy mounted thylacines in museums may also still retain DNA. Many people of Australia support the de-extinction, and habitat still exists. Some of the animal's genes have already been successfully expressed in a mouse fetus after the scientists inserted the thylacine genes into the mouse's genome. The major project, funded through the Australian Museum, to clone the thylacine, ended after scientists failed to obtain enough DNA to create a DNA library for the species.

3 of 14 Pyrenean Ibex Joseph Wolf / Wikimedia Commons / Public Domain Still think cloning extinct animals is impossible? Technically, it's already been done: the Pyrenean ibex or bucardo recently became the first extinct animal to ever become un-extinct — at least, for seven minutes. The cloned fetus, which contained reanimated DNA from the last known living Pyrenean ibex, was successfully brought to term after being implanted in the womb of a living domestic goat. Although the ibex died of lung difficulty seven minutes after birth, the breakthrough points the way forward in cloning preservation programs of extinct species. The last known Pyrenean ibex was a female named Celia, who was killed by a falling tree in 2000. It was her DNA that was used to create the short-lived clone.

4 of 14 Saber-Toothed Cats Sfocato / Shutterstock Looking at the epic canine teeth of these once-fearsome cats of Pleistocene lore, you may wonder whether resurrecting saber-toothed cats is a good idea. Fossil specimens have survived into modern times thanks to the frigid habitats they once roamed. Ancient tar deposits, like those at the La Brea Tar Pits, preserved intact specimens, though whether there is enough ancient DNA to create a database is doubtful. This one fires up the imagination and enthusiasm in a science-fiction scenario, but the realities of finding an unrelated surrogate able to carry the embryo, raising it, and providing suitable habitat mean this one is a long-shot. IUCN guidelines certainly seem to recommend against it.

5 of 14 Moa Joseph Smit / Wikimedia Commons / Public Domain These giant flightless birds, similar in appearance to ostriches and emus but without vestigial wings, were once the world's largest birds. Because moas were hunted to extinction as recently as 600 years ago, their feathers and eggs can still be found relatively intact. Scientists have reportedly extracted moa DNA from ancient eggshells and mapped the genome. Scientists aren't as enthusiastic as some politicians about the odds of a successful moa clone and reintroduction of the species.

6 of 14 Dodo Biodiversity Heritage Library / Flickr / Public Domain Perhaps the world's most notorious extinct animal, the dodo, was driven to extinction a mere 80 years after its discovery. Since the bird's habitat on the island of Mauritius contained no natural predators, the dodo did not evolve effective defenses. This lack of instincts led to extinction through sailors being able to kill them for food quickly. Invasive species introduced from the sailors' ships ate the vegetation that formed the diet of the dodo, as well as the dodo eggs, creating the primary factor causing their extinction. Scientists hope to recover the dodo if they gather enough DNA to create a clone to implant in the eggs of closely related modern pigeon.

7 of 14 Ground Sloth EdenPictures / Flickr / CC BY 2.0 Looking at the fossil remains or model of this ancient creature and you might believe you're looking at a giant bear. These enormous animals were ground sloths, most closely related to the slumbering modern-day three-toed sloth. They make the de-extinction list because giant ground sloths still walked the Earth just 8,000 years ago at the dawn of human civilization. DNA samples have already been extracted from intact hair remains. Because the only surviving relatives of the ground sloth are tiny by comparison, finding a surrogate mother is impossible. But it may someday be possible to develop a fetus in an artificial womb.

8 of 14 Carolina Parakeet James St. John / Flickr / CC BY 2.0 Once the only parrot species native to the United States, the Carolina parakeet was tragically driven to extinction after being hunted for its feathers, which were popular in ladies' hats. The last known specimen died as recently as 1918. Because mounted birds, remnant feathers and eggshells remain in circulation and museums, DNA extraction and cloning of the species could soon become a possibility. Virginia Tech has a project underway to implant a Carolina parakeet genome into the egg of a relative, the Jandaya parakeet. In the bird's favor: there's enough suitable climate for the bird to inhabit, but that raises the risk that the bird could become an invasive species.

9 of 14 Woolly Rhinoceros Charles R. Knight / Wikimedia Commons / Public Domain The woolly mammoth wasn't the only massive hairy creature on the chilly Pleistocene tundra. The woolly rhinoceros also stomped through the Arctic snow as recently as 10,000 years ago. The animal also appears frequently in ancient cave art, such as at Chauvet-Pont-d'Arc Cave in France. Woolly rhinos share many of the same pros as candidates as the wooly mammoth. Well-preserved specimens frequently become exposed in Arctic permafrost. Scientists have successfully sequenced the DNA and a rhinoceros could potentially carry the embryo. However, this victim of climate change lacks suitable areas for repopulation. What habitat does remain is rapidly shrinking due to anthropogenic or human-influenced climate change.

10 of 14 Passenger Pigeon seabamirum / Flickr / CC BY 2.0 As recently as 200 years ago, flocks of passenger pigeons numbering in the billions blanketed the North American sky. By 1914, ruthless hunting campaigns wiped out the species. Now thanks to cloning technology, the animal that was once the most numerous bird in North America might have a second chance. Museum specimens, feathers, and other remnants of these birds still exist, and because they are so closely related to the mourning dove, finding a surrogate mother would be easy. Revive and Restore, an organization that actively seeks to recover extinct species, has a project well underway. They claim that returning passenger pigeons to the forests of North America will serve as a critical species in conserving that ecosystem.

11 of 14 Irish Elk Charles R. Knight / Wikimedia Commons / Public Domain Another megafauna to fall victim to the ending of an ice age was the Irish elk. Calling this animal an elk is a misnomer, as DNA analysis has shown that it was more closely related to fallow deer. These results make the Irish Elk the largest deer to have ever lived. Its antlers alone measured as much as 12 feet across. As with other animals that lived in the icy north during the Pleistocene, preserved specimens of the Irish elk can be readily found in melting permafrost, making it a prime candidate for being cloned technically. The reality that the inability to cope with the warming climate led to their first extinction and the lack of any habitat for large mammals in Ireland means this species would only have a future as a zoo or lab animal.

12 of 14 Baiji River Dolphin Institute of Hydrobiology, Chinese Academy of Sciences / Wikimedia Commons / CC BY-SA 4.0 Declared "functionally extinct" in 2006, the Baiji River dolphin became the first cetacean to go extinct in modern times due to human influence. Because of its recent extinction, however, DNA can still be easily extracted from remains. Like with many extinct species, the question remains about whether the Baiji River dolphin would have a home to return to after being resurrected. The Yangtze River system, this dolphin's natural habitat, remains heavily polluted. There's currently not enough governmental support or money to correct the issues that led to the extinction of the dolphin in the first place. Industrial pollution created during the manufacture of many products shipped to the west, including common household goods, electronics parts and materials, and fashion drives the pollution. Another source, now remedied, was the enormous amounts of plastics that the Western world shipped to China in the name of recycling. China banned those imports in 2018.

13 of 14 Huia Haplochromis / Wikimedia Commons / CC BY-SA 3.0 This uniquely beaked bird, once endemic to the North Island of New Zealand, became extinct in the early 20th century after museum demand for mounted specimens reached a peak. Due in part to the bird's popularity as a mascot and national symbol within New Zealand, a project was launched in 1999 to clone and resurrect the huia. The mapping of the genome has been successful. Sadly, the South Island Kokako, the species most closely related to the huia, may have already joined the huia in extinction. The other closely related species, the North Island Kokako, currently listed as near threatened by the IUCN, also faces eradication due to introduced invasive species in its ecosystem. Efforts to bring back the huia may end up using money that effectively preserves extant species instead.