The image of the woolly mammoth, saber-toothed cat and dodo bird stepping out of a beaker on the cover of National Geographic’s April issue says it all. Science has found a way to bring back some long-extinct species — or at least, facsimiles of them.
In truth, the goat-like bucardo, or Pyrenean ibex, is the only extinct animal scientists have actually revived. In 2003, biologists managed to clone an offspring from frozen skin cells from the last survivor, which died in 2000. The clone, however, lived for only a few minutes after its birth. Since then, advances in cloning technology have made it possible to bring back any species if there is a remnant of DNA.
But with so many habitat pressures on the wild species that are already here and with so many on the brink of extinction, is bringing back those we’ve already lost a good idea?
Objects in mirror are closer than they appear
The term that scientists give to this new technology is de-extinction. But unlike what happened in the popular film Jurassic Park, a return of the dinosaurs isn’t possible. The only animals with a hope of being brought back are those that died within the past few tens of thousands of years and that left behind remains that still contain intact cells or, at the very least, enough ancient DNA to reconstruct their genome. That means that a species would have had to be present within the time that humans have roamed the Earth. The dinosaurs, which vanished about 65 million years ago, won’t be making a reappearance due to natural rates of decay. While you won’t have to fear that a Tyrannosaurus rex will be moving into your neighborhood, a Neanderthal might.
That’s probably a long ways off. But like the famous shot in Jurassic Park of the printed words on a vehicle’s rearview mirror, “objects are closer than they appear,” Australian scientists say they‘re about to resurrect an extinct type of frog that gives birth through its mouth. Harvard scientists are working to bring back the passenger pigeon, and Russian researchers plan to re-create a woolly mammoth from DNA recovered from the Siberian permafrost.
Since the only species capable of being revived are those that we’ve most likely had a hand in exterminating — by hunting them, destroying their habitats, or spreading diseases among them — some say we are obliged to bring them back.
Other advocates would argue that de-extinction is a scientific breakthrough that demands follow-through. The same cloning and genomic engineering technologies and methodologies being developed for de-extinction could also aid in saving endangered species, especially ones that are hard to breed in captivity.
And then there are those who believe that it would just be cool to stand in the presence of a being, such as a Tasmanian tiger, that we’ve only seen in artists’ renderings, faded photographs or grainy film footage.
You can’t go home again
But not everyone agrees that we should bring back extinct species just because we can. With rapid habitat loss, rampant hunting and poaching, and climate change threatening the extinction of half of all our present plants and animals by 2100, a priority should be put on conserving the species we still have. Why invest millions of dollars in bringing back a handful of what we’ve already lost when there are millions still waiting to be discovered and protected?
Opponents of de-extinction also argue that you’re not really bringing back the exact same creature. Usually, a “cousin” of the extinct species is used to bear the re-created sperm and eggs. When those animals are born or hatched, then they are bred. Successive generations are then selectively interbred for traits that make an individual more and more like the vanished species. So, while the end product from a rock pigeon, a close relative of a passenger pigeon, might be a bird that has passenger pigeon characteristics engineered into it, is it really a passenger pigeon?
Too, putting a once-extinct species back into the wild is going to be difficult. In 1972, the wild Arabian oryx went extinct. It was reintroduced to a refuge in central Oman in 1982. By 1996, there were 450 wild oryx living in the preserve. Poachers wiped out almost all of those animals. Subsequently, development of nearby oil reserves took a toll on the natural integrity of the site, and Oman decided to reduce the size of the protected area by 90 percent. The Arabian Oryx Sanctuary, which had been inscribed with World Heritage status in 1994, was delisted in 2007. It seems we humans haven’t learned much.
Unfortunately, as with the wild Arabian oryx, most brought-back animals would probably find no place to call home. Chinese river dolphins became extinct in 2006 due to pollution and other pressures from the human population on the Yangtze River. Conditions there haven’t changed. Around the world, a human-spread pathogen called the chytrid fungus is decimating the world’s frog populations. Every year, humans ship millions of amphibians around the world in a largely unregulated pet and food trade. When an infected frog arrives in a new location, it can spread disease to native populations if it escapes, when it is set free, or when water from its holding tank is released into the environment. If the Australian scientists do resurrect their gastric-brooding frogs (the ones that give birth through their mouths) and release them into their old mountain streams, the frogs could promptly become extinct again.
Learning that the last of any animal has died on our watch is tough to take. I think watching its kind go extinct again may be even harder to bear.
Do you think we should bring back long-extinct species?
Feature photo: Frog populations have been declining worldwide at unprecedented rates. Almost one-third of the planet’s amphibian species are threatened with extinction. ©Patrick Endres