Name: Altabra Train (Triolimnas quareri Altabranus)
Where it lives: Aldabra – A coral atoll off the southeast coast of Africa
What it eats: Insects
Why it's awesome: Off the southeast coast of Africa, north of Madagascar, the coral limestone islands of the Altabra Atoll are home to a humble and surprising bird that evolved twice to become flightless.
The Altabra train is unremarkable at first glance. It is about the size of a chicken, with a slender gray back, a rusty red head and breast, and a white throat. It is a subspecies of the white-throated rail (Triolimnas Quarry) and is the only flightless bird living in the Indian Ocean, since birds such as the dodo have been driven to extinction by humans (Hood ruffs)
A study published in 2019 Zoological Journal of the Linnean Society A study of the fossil record of tracks in Altabra found evidence of a flightless train in the valley before it sank beneath the waves 136,000 years ago. This phenomenon caused an „almost complete reversal in the fauna,” the lead author said Julian HumeA paleontologist at the Natural History Museum in London, A Report At the time.
This flood, which lasted until about 118,000 years ago, led to the extinction of the flightless rail subspecies, but then something remarkable happened.
When the atoll reappeared, the white-throated rail—which could fly—recolonized the atoll and began its evolution toward flight again. The researchers found leg fossils from rails dating back about 100,000 years were heavier and stronger than white-throated rails. According to the study authors, this indicates that the scales on the coral reef have become heavier and have lost the ability to fly.
Related: See 'incredible' photos of male and female bird
Flightlessness appears to be a beneficial trait in this context. These birds lay their eggs on the ground, so having strong legs to run straight after hatching will help them survive. „As they grow, the last to develop on the rails are the pectoral muscles and the wing muscles,” Hume said.
Once again losing the ability to fly, the altabra train essentially evolves twice, rising from the dead through a process known as „iterative evolution” — where one species dies out, but another species arrives and develops the same traits. Like lost.
„I can find no other instance of this happening, where you have a record of the same bird being unable to fly twice,” Hume said. „It's not like two different species are colonized and flightless. It's the same ancestral bird.”