Kiwi DNA link spurs rethink of flightless birds


WELLINGTON, New Zealand (AP) — Research linking New
Zealand’s diminutive kiwi with a giant extinct bird from Africa is
prompting scientists to rethink how flightless birds evolved.
report published Friday in the journal Science says DNA testing
indicates the chicken-size kiwi’s closest relative is the elephant bird
from Madagascar, which grew up to 3 meters (10 feet) high and weighed up
to 250 kilograms (550 pounds) before becoming extinct about 1,000 years
The authors say the results contradict earlier theories that
the kiwi and other flightless birds, including the ostrich and emu,
evolved as the world’s continents drifted apart about 130 million years
Instead, they say, it’s more likely their chicken-size,
flight-capable ancestors enjoyed a window of evolutionary ascendancy
about 60 million years ago, after dinosaurs died out and before mammals
grew big.
Those birds, the authors say, likely flew between the
continents, with some staying and becoming the large, flightless species
we know today.
Alan Cooper, a professor at the University of
Adelaide in Australia and a co-author of the paper, said the DNA results
came as a huge surprise given the differences in size and location
between the kiwi and elephant bird.
"This has been an evolutionary
mystery for 150 years. Most things have been suggested but never this,"
he said. "The birds are about as different as you can get in terms of
geography, morphology and ecology."
Cooper, a New Zealander by birth, is hoping the paper will also bring him a measure of redemption.
because two decades ago, Cooper and other scientists discovered genetic
links between the kiwi and two Australian flightless birds, the
cassowary and the emu. That led to New Zealanders believing their iconic
bird might have come from Australia, a traditional rival.
"There was a huge outpouring of angst," Cooper said. "New Zealanders weren’t too
nation’s identity is so entwined with the bird that New Zealanders call
themselves kiwis and have also given the name to their currency and the
But it turns out that if the emu was a cousin to the
kiwi, the elephant bird was a sibling. Cooper said it has taken until
now for DNA techniques to advance enough to get a usable result from the
ancient bones of the Madagascan bird.
Cooper said the bird took
its name from Arabic legends that suggested it was so fearsome it could
grab an elephant with its talons.
There’s little basis for the
legend given the bird was a flightless herbivore. In fact, it was likely
humans that hunted it into oblivion, Cooper said.
Trevor Worthy, a
research fellow at Australia’s Flinders University and a paper
co-author, said it’s likely the kiwi stayed small and took to eating
insects at night because it didn’t want to compete for habitat and food
with another New Zealand flightless bird, the moa, which is also now
extinct. He said it’s strange the kiwi and elephant bird are such close
"One got big, one stayed little," he said.
University professor David Penny, who wasn’t involved in the research
but who peer reviewed it for Science, said the results are very
interesting and help complete the puzzle of flightless birds.

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