The Aldabra Rail Is A Bird Species That’s Defied The Odds And Come Back From The Dead Twice, Re-Evolving Back Into Existence After Facing Extinction
When a species goes extinct, that’s usually the end of its kind. However, a bird known as the Aldabra rail has made a miraculous return from the brink of death, not just once but twice!
Over the years, the bird has re-evolved its way back into existence in a way that challenges scientists’ understanding of nature. Here’s how the flightless, feathered creature defied all odds and came back from the dead.
At first glance, the Aldabra rail probably won’t strike you as the awe-inspiring bird it really is. It is similar in size to a chicken, with a rust-red head, a back flecked with gray, and a white throat. It is a descendant of the white-throated rail.
The Aldabra rail’s native habitat is the Aldabra Atoll in the Indian Ocean. It is made up of a series of coral limestone islands that lie off the southeast coast of Africa, north of Madagascar.
In the past, the atoll had been completely submerged underwater multiple times, wiping out every existing species each time.
Yet, the Aldabra rail has always managed to come back through a rare process called iterative evolution. The bird is a species with an ancestral lineage that allows it to repeat the same evolutionary path.
According to a 2019 study published in the Zoological Journal of the Linnean Society, evidence of the flightless Aldabra rail was found on the island before they were submerged around 136,000 years ago.
For a few thousand years, it seemed that the species was gone for good. But something remarkable happened.
When the atoll resurfaced, the white-throated rail, which was able to fly, re-colonized the region at some point, beginning once again, the Aldabra rail’s evolution as a flightless version of its ancestor. Researchers studied leg fossils on the island dating back to around 100,000 years ago.
CaganHakki – stock.adobe.com – illustrative purposes only, not the actual bird
The fossils showed that the legs of the Aldabra rail were heavier and more robust than the legs of the white-throated rail, indicating that the birds on the atoll were losing the ability to fly.
The lack of predators on the island did not make flight a necessary trait for survival. As flightless birds, the Aldabra rail lays their eggs on the ground and has strong legs to run around on straight after hatching. This is the first time that iterative evolution has been documented in rails.
“There is no other case that I can find of this happening where you have a record of the same species of bird becoming flightless twice,” said Dr. Julian Hume, a paleontologist at the Natural History Museum in London.
“It wasn’t as if it were two different species colonizing and becoming flightless. This was the very same ancestral bird.”
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