Life is tweet :
First bird had hearing like an emu’s
Archaeopteryx, the first known bird, had a hearing range similar to
the modern-day emu’s, according to a study published that boosts the
avian claims of this descendant of the dinosaurs.
About the size and shape of a European magpie, Archaeopteryx
lithographica appeared on the scene around 150 million years ago, in the
Jurassic era.
The first fossil was unearthed in Bavaria, southern Germany, in 1861,
and so far eight specimens have come to light. Scientists at the Natural
History Museum in London used a computed tomography (CT) scanner to make
a 3-D picture of the inner ear of Archaeopteryx, modern birds and
reptiles.
Their area of interest was the cochlear duct — the bony part of the
inner ear that houses the sensory tissue. The size of this duct is a
good indicator of an animal’s hearing range.
According to their calculations, Archaeopteryx had an average hearing
range of approximately 2,000 hertz. “This means it had similar hearing
to modern emus, which have some of the most limited hearing ranges of
modern birds,” said palaeontologist Paul Barrett.
By comparison, the human voice is general in the range of 80 to 1,100
Hz, and good human hearing runs from around 20 to 20,000 Hz.
The study, appearing in the British journal Proceedings of the Royal
Society B, could unlock new clues about the enigmatic Archaeopteryx, the
authors hope.
A long debate has raged over this species, with some experts arguing
that its mixture of features show it to be more a feathery theropod — or
two-footed dino — than a primitive bird. But the paper gives a powerful
push to the pro-avian camp. “This adds yet more information about how
bird-like Archaopteryz was,” team member Angela Milner said in a press
release.
PARIS,AFP |