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How did flightless birds spread across the world?

How Did Flightless Birds Spread Across The World?

Here's a riddle: how did an order of flightless birds manage to spread to places they would have had to fly to? Rheas live in South America, cassowaries and emus in Australia, kiwis in New Zealand and ostriches in Africa. They're all related and they're all land-dwelling. How does that work?

That's kind of a tough one for evolutionary scientists. The dominant answer is that the birds spread to where they're found today way back before the continents broke up. But DNA tests are starting to make the issue even more puzzling.

A new study from the University of Adelaide looked at the DNA of this big guy, the elephant bird, one of the biggest birds to have ever existed. It lived on Madagascar and died out sometime in the last few hundred years.

The researchers were trying to work out whether the elephant bird was related to the moa, another feathered behemoth from New Zealand that died out around the same time. Instead, it was more closely related to this little guy, New Zealand's iconic kiwi.

And it turns out the moa's closest relative is another chicken-sized bird called the tinamou, which lives - get this - in South America. Another twist: some of them can even fly.

The study's lead author Andrew Cooper told New Scientist, "‚ÄčIn both cases, the moa and the elephant bird, the nearest relative is on the other side of the world."

Analysis of the DNA samples showed the elephant bird and the kiwi last shared a living relative around 50 million years ago - way after the continents had already split up. So Cooper says the answer to how flightless birds spread all over the world is simple: they flew there.

National Geographic's Ed Yong says Cooper's research supports a newer theory about the flightless bird family: that they "evolved from small, flying birds that flapped their way between continents and independently lost the ability to fly on at least six separate occasions."

That would make flightlessness an example of convergent evolution, when two species independently evolve the same traits, like hard shells in different kinds of pill bugs or fingerprints in humans and koalas.

So that's probably how you solve the riddle of the flightless birds. But it turns out there's another interesting subplot here.

Back in 1992, Cooper published a study in Proceedings of the National Academy of Sciences that showed kiwis were likely descended from the Australian emu. And that didn't go over too well in New Zealand.

A writer for the New Zealand Herald said, "Our national bird and treasured namesake ... was, of all things, an Aussie immigrant." and dubbed the study "one of the greatest wrongs ever inflicted upon New Zealanders."

Cooper seems to hope the new study makes up for it, though, saying "‚ÄčIt's great to finally set the record straight. ... I can only apologise it has taken so long!"

Join the discussion

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sirwilhelm May 23 2014 at 6:45 AM

If you don't really know, you can make up a story, and call it evolution.

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6 replies
jenny1918joe May 23 2014 at 7:53 AM

Kind of like wondering how Oblama got to the white house---talk about a flightles bird !!

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5 replies
Dad May 23 2014 at 4:21 AM

science is not ALL theoretical. you study the facts and then build a theory based on those and then work on PROVING that theory. God didn't build the atom bomb. there was a theory, then the theory was proven. God didn't make hereford cattle, or german shepards, or dobermans, or labrador retrievers. We manipulated animals in the same way nature does and you are a moron if you don't see that. you can have faith and not be stupid about it.

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3 replies
maryochamp64 May 23 2014 at 12:22 AM

Birds are fascinating creatures. I enjoyed watching and reading the article and video. Birds should be loved and respected.

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1 reply
cvchix maryochamp64 May 23 2014 at 9:25 AM

and eaten.

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1 reply
terwalk2 cvchix May 23 2014 at 5:03 PM

u ever eat a sparrow? try being more specific idiot

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spock4777 May 23 2014 at 2:15 AM

Why do scientists continue to deny the truth that God created everything and evolution is a total lie...at least to the degree that they are pushing it.

God created two original kinds in which all kinds of that kind descended from.

No evolution needed just the passing of genetic traits from the two original kinds to their offspring forming all the creatures that belong to their kind.

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15 replies
fullyscottish40 May 23 2014 at 9:07 AM

it was the aliens ,man. they found out kiwis taste like chicken!

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mark and sheri May 23 2014 at 2:43 AM

Space Aliens and telekinesis. Just listen to Coast to Coast at night.

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sindfetish May 23 2014 at 12:29 PM

Ark...it was the ark.

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1 reply
Vocem Meam sindfetish May 23 2014 at 1:52 PM

And the Ark was a spaceship that harbored 2 DNA samples of each species. The Aliens saved life from a natural flood/tsunami or whatever disaster it faced.

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endmillll May 23 2014 at 8:13 AM

Add a comment..I'm betting he got the welfare system to pay for it.

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MICHAEL May 23 2014 at 11:44 AM

this new format from aol sucks.

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aol~~ 1209600


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