Flightless Wonder: Ancient Elephant Bird Flew Across Continents

The now-extinct elephant bird of Madagascar, though flightless, somehow flew across the world to evolve into its present day flightless relatives.

The largest species of flightless birds alive today are called ratites, and include the ostrich, emu and rhea of Africa, Australia and South America, respectively. Though large, they were once just as massive as the elephant bird, which stood up to nine feet tall and weighed as much as 600 pounds, according to The New York Times.

Scientists aren't sure precisely when these flightless birds became extinct, and for decades have studied DNA from their measly remains to figure it out. Finally, a team of Australian researchers has now recovered sizable chunks of DNA from two different species of elephant birds. They were surprised to find that the closest relative of the gigantic bird is the tiny New Zealand kiwi, also a ratite.

"It was a real surprise that elephant birds are most closely related to kiwis - it's completely unprecedented," lead study author Kieren Mitchell, an evolutionary biologist, told Live Science. "No one in over a century of study has proposed this relationship. This is because the two groups are just so different."

Scientists long thought that different species of ratites evolved from equally flightless ancestors after the splitting of the supercontinent Gondwana - a landmass that included what is now Africa, South America, Australia, Antarctica, India, Arabia, New Zealand and Madagascar - some 130 million years ago.

It would seem that the African ostrich and the Madagascan elephant bird were most closely related given their strong similarities, but instead it is the six-pound kiwi.

The new study suggests that ratites did not evolve from populations of a common flightless ancestor that were separated by continental drift, but rather they evolved from ancestors that flew long distances to different parts of the world and then evolved independently to be flightless.

"We have to completely reconsider the origin of ratites as a whole," Mitchell said. "It totally changes our understanding of how these lineages moved around and arrived at their current homes."

The scientists detailed their findings in the May 23 issue of the journal Science.