On the island of Mauritius, east of Madagascar in the Indian Ocean lived a flightless comical-looking bird destined for extinction, the Dodo. It may have vanished forever, but on a nearby island to the northeast called the Aldabra Atoll, another flightless bird called the white-throated rail went extinct and came back from the dead. The chicken-sized brown bird was resurrected in the Seychelles through a process called iterative evolution, evolving flightlessness on multiple occasions after the island sunk beneath the sea and re-emerged thousands of years later.
The rail is the last surviving flightless bird in the Indian Ocean. It’s the first time the extremely rare iterative evolution process has been seen in rails and a highly significant find for evolution in birds.
David Martill, of the University of Portsmouth, co-author of the study about the rail stated:
“We know of no other example in rails, or of birds in general, that demonstrates this phenomenon so evidently,” said Martill.
Scientists discovered that the white-throated rail, a flightless bird that went extinct 136,000 years ago, came back from the dead through a process called “iterative evolution.”
#todayilerned #walkingdead pic.twitter.com/yTx9TShRgB
— Let's Get Sciencey (@letsgetsciencey) May 12, 2019
The scientists found fossils from before the time when Aldabra sank beneath the waves 136,000 years ago and compared them to more recent fossils when sea levels fell, exposing the island atoll once more.
Avian paleontologist, Julian Hume of London’s Natural History Museum, the study’s lead author stated:
“These unique fossils provide irrefutable evidence that a member of the rail family colonized the atoll, most likely from Madagascar, and became flightless independently on each occasion,” said Hume.
A bird species in the Seychelles came back from extinction, according to a new study.
Researchers found fossil evidence proving the flightless Aldabra rail went extinct when their island flooded 136K years ago… and evolved back when new birds colonized the island years later. pic.twitter.com/sCYaqNubJx
— AJ+ (@ajplus) May 10, 2019
The island of Aldabra is unique in all the world.
“Only on Aldabra, which has the oldest palaeontological record of any oceanic island within the Indian Ocean region, is fossil evidence available that demonstrates the effects of changing sea levels on extinction and recolonization events,” Martill said.
The flightless rails evolved from a parent species living on nearby Madagascar. When a lucky few birds managed to make it to Aldabra, they found no predators there. Consequently, the need to fly became unnecessary, and they slowly lost their ability. Then the island submerged and all the flora and fauna on the island were killed.
I helped Julian Hume by making figures for his paper about repeated evolution of flightlessness in Rails on Aldabra. I got interviewed and said that flightless birds are more vulnerable to extinction. @Noguesbravo @Carsten_Rahbek @Macroecology https://t.co/WcrDmYQwwo
— Julia Heinen (@JuliaHHeinen) May 11, 2019
Julian Hume is also an artist and has done extensive work to learn more about the Dodo, which went extinct due to humans around 1680. Using a Dodo skeleton, he has been able to create a virtual 3D model of the iconic bird. He suggests that the bird was not fat, slow, or stupid, as it has been typically depicted in exaggerated pictures. In fact, the birds, which are essentially giant ground pigeons, were described as slim, athletic, and fast by mariners who visited Mauritius island. Their closest living relative may be the Nicobar Pigeon.
— Natural History Museum (@NHM_London) October 15, 2016
Scanning an extremely rare near-complete dodo skeleton, Hume found that the Dodo was likely very smart and well-adapted to life on the isolated island.
“CT scans of skulls in the Museum’s collection show that dodos were relatively intelligent birds, with large brains. They also had large olfactory bulbs, which process smells. Given their inability to fly, it suggests their brain was well-suited to sniffing out food on the ground.”
Using DNA sequencing, they hope to pin down the Dodo’s relationship to other birds. If they can determine the ancestor then who knows, maybe at some point in the distant future, the Dodo could evolve again after millions of years, similar to the white-throated rail. The likelihood is very small indeed and we’d need millions of years to witness it.
On the other hand, Hume does not rule out the possibility of “recreating the Dodo in the distant future using DNA.”
See Hume discuss the Dodo below:
See more animals that “came back from extinction” below, including one that you can probably find in your town at the pet store today.
Featured image: Screenshot via YouTube