Garrison Hilliard
2006-03-15 20:22:53 UTC
Singing frog's 'ultrasonic croak'
By Helen Briggs
BBC News science reporter
A rare Chinese frog has entered the record books as the first amphibian known to
communicate using ultrasound.
Until now, only a few mammals - such as bats, whales and dolphins - have been
found to use the very high frequency sound to contact each other.
The frog may have evolved the mechanism to be heard above the babble of running
water, scientists tell this week's edition of the journal Nature.
The frog lives alongside fast-flowing streams in Anhui Province, China.
During the rainy season, the water level rises dramatically, creating a noise
that drowns out the calls of many small animals.
Amolops tormotus can be heard above the din by producing ultrasonic (greater
than 20 kilohertz) calls beyond the spectrum of the background hubbub.
The Chinese frog's vocalisation is very unusual. Most frog calls go either up or
down only; but A. tormotus uses multiple upward and downward sweeps of notes
more in keeping with the sounds made by birds, whales or primates.
Nature's way
A team led by Albert Feng, a US professor, visited the bank of China's Tao Hua
Creek in search of the frog.
They heard the warbling melody of what they thought was a bird coming from some
undergrowth.
It turned out to be the song of a male frog of the very species they wanted to
study.
Dr Feng wondered whether other members of the species were able to hear and
respond to the calls or if it was just for show.
He devised an experiment to find out. The team recorded a frog's calls, split
them into their constituent frequencies and tested other frogs' responses to
them in the wild.
They found that most of the frogs responded to ultrasonic and audible sound
ranges, half of them sending back their own ultrasonic and audible calls in
response.
Only male frogs were tested and it is not yet known whether female frogs, which
have a different ear structure, use ultrasound.
"Nature has a way of evolving mechanisms to facilitate communication in very
adverse situations," said Dr Feng.
"One of the ways is to shift the frequencies beyond the spectrum of background
noise. Mammals such as bats, whales and dolphins do this, and use ultrasound for
their sonar system and communication. Frogs were never taken into consideration
for being able to do this."
'Unexpected' communication
Dr Feng believes the capacity to respond to ultrasound may well be found in
other amphibians and birds.
The fact that it has been found in amphibians, which are on a different
evolutionary pathway from mammals, suggests it has evolved several times
independently in the animal kingdom.
"Humans have always been fascinated by how some animals can discern their world
through a sensing system vastly different from our own," said Feng, a professor
of molecular and integrative physiology at the University of Illinois at
Urbana-Champaign.
"The electromagnetic sense in fishes and homing pigeons, polarised light vision
in ants, chemical sensing of pheromones in insects and rodents, echolocation by
ultrasound in bats and dolphins, are just a few examples.
"Frogs that can communicate with ultrasound adds to that list and represents a
novel finding, because we normally think such ability is limited to animals
equipped with a sophisticated sonar system.
"This suggests that there are likely many other examples of unexpected forms of
communication out there."
Visual displays
Professor Tim Halliday of the Department of Biological Sciences at The Open
University, UK, said other types of frog had also been able to solve the problem
of living near noisy streams, where they cannot make themselves heard.
"At least two other frog species, one from Borneo, the other from South America,
have resolved this dilemma in a quite different way," he told the BBC News
website.
"Rather than calling to attract females and deter rival males, they use visual
displays, waving their brightly coloured feet."
Dr Feng's lab at the University of California at Los Angeles worked with
colleagues at the Shanghai Institutes of Biological Sciences; and the Institute
of Biophysics in Beijing.
Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/4806906.stm
Published: 2006/03/15 18:01:12 GMT
By Helen Briggs
BBC News science reporter
A rare Chinese frog has entered the record books as the first amphibian known to
communicate using ultrasound.
Until now, only a few mammals - such as bats, whales and dolphins - have been
found to use the very high frequency sound to contact each other.
The frog may have evolved the mechanism to be heard above the babble of running
water, scientists tell this week's edition of the journal Nature.
The frog lives alongside fast-flowing streams in Anhui Province, China.
During the rainy season, the water level rises dramatically, creating a noise
that drowns out the calls of many small animals.
Amolops tormotus can be heard above the din by producing ultrasonic (greater
than 20 kilohertz) calls beyond the spectrum of the background hubbub.
The Chinese frog's vocalisation is very unusual. Most frog calls go either up or
down only; but A. tormotus uses multiple upward and downward sweeps of notes
more in keeping with the sounds made by birds, whales or primates.
Nature's way
A team led by Albert Feng, a US professor, visited the bank of China's Tao Hua
Creek in search of the frog.
They heard the warbling melody of what they thought was a bird coming from some
undergrowth.
It turned out to be the song of a male frog of the very species they wanted to
study.
Dr Feng wondered whether other members of the species were able to hear and
respond to the calls or if it was just for show.
He devised an experiment to find out. The team recorded a frog's calls, split
them into their constituent frequencies and tested other frogs' responses to
them in the wild.
They found that most of the frogs responded to ultrasonic and audible sound
ranges, half of them sending back their own ultrasonic and audible calls in
response.
Only male frogs were tested and it is not yet known whether female frogs, which
have a different ear structure, use ultrasound.
"Nature has a way of evolving mechanisms to facilitate communication in very
adverse situations," said Dr Feng.
"One of the ways is to shift the frequencies beyond the spectrum of background
noise. Mammals such as bats, whales and dolphins do this, and use ultrasound for
their sonar system and communication. Frogs were never taken into consideration
for being able to do this."
'Unexpected' communication
Dr Feng believes the capacity to respond to ultrasound may well be found in
other amphibians and birds.
The fact that it has been found in amphibians, which are on a different
evolutionary pathway from mammals, suggests it has evolved several times
independently in the animal kingdom.
"Humans have always been fascinated by how some animals can discern their world
through a sensing system vastly different from our own," said Feng, a professor
of molecular and integrative physiology at the University of Illinois at
Urbana-Champaign.
"The electromagnetic sense in fishes and homing pigeons, polarised light vision
in ants, chemical sensing of pheromones in insects and rodents, echolocation by
ultrasound in bats and dolphins, are just a few examples.
"Frogs that can communicate with ultrasound adds to that list and represents a
novel finding, because we normally think such ability is limited to animals
equipped with a sophisticated sonar system.
"This suggests that there are likely many other examples of unexpected forms of
communication out there."
Visual displays
Professor Tim Halliday of the Department of Biological Sciences at The Open
University, UK, said other types of frog had also been able to solve the problem
of living near noisy streams, where they cannot make themselves heard.
"At least two other frog species, one from Borneo, the other from South America,
have resolved this dilemma in a quite different way," he told the BBC News
website.
"Rather than calling to attract females and deter rival males, they use visual
displays, waving their brightly coloured feet."
Dr Feng's lab at the University of California at Los Angeles worked with
colleagues at the Shanghai Institutes of Biological Sciences; and the Institute
of Biophysics in Beijing.
Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/4806906.stm
Published: 2006/03/15 18:01:12 GMT