distances through sounds in the infrasound range.
They communicate in a frequency of just 20 hertz, a level so low that
humans can hardly hear it.
But it's still unclear how they produce these sounds. Do they create
it similarly to humans and other mammals by sending airflow through
the vocal folds?
Or is it a muscle vibration similar to a purring cat? With the help of
international colleagues, Christian Herbst from the University of
Vienna came to the conclusion that elephants communicate like humans
by airflow.
The researchers, among them Roland Frey from the Leibniz Institute for
Zoo and Wildlife Research in Berlin, examined the larynx of an
elephant that died of natural cause last autumn in the Berlin zoo.
"We placed the larynx on a pipe and blew heated and dampened air
through the vocal folds. We basically simulated a lung in the
laboratory," explained Herbst.
With a high-speed video camera, the researchers were able to view a
movement of the vocal folds as well as audio recordings of the low
frequency sounds.
Herbst and his colleagues concluded that the frequency range
communicated through the elephant's vocal folds ranged from that of
echo sounder bats to that of a singing human.
The vocal folds are in the larynx and consist of the vocal muscle and
vocal cord. They produce tones with the help of their position and
tension.
"We have known for 150 years that the voice of a human is generated in
the larynx. But you can't really examine animals endoscopically," said
Herbst.
The researchers presented their findings in the magazine Science. (dpa/NAN)
No comments:
Post a Comment