Following on from my earlier feature: De-extinction – The future of conservation, here’s a quick guide to 5 of the species scientists are talking about bringing back from the dead. As you will see, the candidates proposed by Revive and Restore are heavily biased towards extinct vertebrates, which is not an accurate reflection of all extinctions. It’s high time scientists paid more attention to reviving the less glamorous extinct plants and invertebrates, but until they do, don’t shoot the messenger! If you want to find out more information about this topic, I recommend watching some of the videos from the recent TEDx De-extinction conference here. At the bottom of the post I’ve set up a poll where you can vote for the species you’d most like to resurrect, and please leave your comments on de-extinction also.
Is it a zebra? Is it a horse? No, it’s a quagga. First described in 1778, only a century later it went extinct. Retrospective DNA analysis has since shown that the quagga was not a separate species, but in fact a subspecies of the common Plains zebra that had diverged around 200k years ago. It was characterised by zebra-like stripes on the front half of its body, fading to solid a solid brown colour on the rear half, with a white underside and legs. It died out as a result of over-hunting, because it was seen as a competitor to grazing livestock by farmers in its South African grassland habitat. In 1989 a project was set up to try to bring this animal back from extinction and restore it to this habitat. This de-extinction project aims to selectively breed plains zebras until they display quagga characteristics.
2. Thylacine (Tasmanian Tiger)
The thylacine was a carnivorous marsupial predator that lived in Australia & New Guinea. Despite surviving European settlement in Australia, by 1936 it was recorded as extinct, two months after the Tasmanian government first moved to protect it. The reasons for its decline and subsequent extinction are unproven, but are believed to be due to disease, hunting and the introduction of domesticated dogs. Although similar in form to many mammals, the thylacine is very distantly related to them being a marsupial. It was a nocturnal creature, and its wild habitat is likely to have been eucalyptus forests, wetlands or grasslands. There are numerous preserved museum specimens of the thylacine and these have been used to extract DNA from in order to sequence its genome. Eventually it is hoped that the information gathered could be used to clone thylacines and bring them back from extinction, though there is currently a long way to go.
3. Gastric-brooding Frog
This weird and wonderful genus contained 2 frog species native to Queensland, Australia. They possessed a unique method of rearing young. The female swallowed her eggs after laying, incubating them in her stomach for 6 weeks before they emerged from her mouth as tapoles and froglets. Sadly these frogs went extinct in the 1980s as a result of habitat loss and disease. Given how recent the extinction was, numerous frozen specimens of the species were stored. Last month, scientists announced that they had managed to create an embryo clone of the frog from cell nuclei DNA in the stored specimens. Although this project is at its early stages, there is potential for the gastric brooding frog to one day be resurrected from extinction. There are several close relatives of these frogs that cloned embryos could be implanted into, and this is likely to be successful because amphibian embryos aren’t exposed to their hosts’ immune system as mammal embryos would be.
4. Elephant Bird
Elephant birds were a family of enormous flightless ratites which lived on the island of Madagascar. It is not clear exactly when they went extinct, but estimates range from the 16th to 18th centuries. When they were alive, elephants birds were the largest birds in existence, weighing around 400kg and measuring up to 3m tall. Their eggs are often still found as fossil fragments, this was the subject of a BBC documentary ‘David Attenborough and the Giant Egg‘. Unsurprisingly, it is the size of the adults and their eggs that contributed to their decline. One of these eggs could feed an entire family of humans. Elephant birds are currently listed as a candidate de-extinction species on the Revive & Restore website.
5. Steller’s Sea Cow
Steller’s sea cow was a herbivorous marine mammal, closely related to modern-day manatees. It was first described by the naturalist Georg Steller in 1741, but just 27 years later had been hunted to extinction by Europeans. It is likely to have been around 9m in length, and would have weighed approximately 8 tons. The slow-moving and tame animal was an easy target for hunters. Its large size made it an ideal source of food, and its skin was used to make boats. When it was discovered by Steller, there is likely to have been only 1 population remaining of less than 1500 vulnerable individuals. This species is listed as a de-extinction candidate because hunting can be more easily controlled nowadays. However, it is unlikely we will see this species alive again in our lifetime, as any potential surrogate mothers for its clones would have to be extraordinarily large.