Monday, March 20, 2006

Chinese Torrent Frogs Share Bats' Ultrasonic Capabilities

Not only can a rare Chinese frog sing like a bird, it can also apparently hear like a bat, according to new research.

Albert S. Feng of the University of Illinois at Urbana-Champaign and colleagues previously reported that male torrent frogs that live in an area west of Shanghai produced calls that were remarkably similar to bird songs.

In a new study, published in Thursday's issue of Nature, Feng and his colleagues determined that the creatures also communicate with one another through high-frequency ultrasonic calls, which previously only bats, marine mammals and some rodents were known to use.

Feng and his colleagues recorded the frogs' audible and ultrasonic calls and then studied how eight other males responded to them, finding that most of them responded to calls in both the audible and ultrasonic ranges.

Feng and his colleagues speculated the frogs evolved the ability so they could hear each other above the sound of waterfalls and other noise in their mountainous habitat.

"Nature has a way of evolving mechanisms to facilitate communication in very adverse situations," Feng said. "One of the ways is to shift the frequencies beyond the spectrum of the 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."

-- Rob Stein

Fishing Fleets Overexploiting Seas at High Rate, Study Warns

Highly mobile fishing fleets are exploiting the sea's resources at an unsustainable rate, according to a new paper published Friday by more than a dozen international researchers in the journal Science.

The paper, which looks at how "roving bandits" swoop in and plunder fisheries at a rapid rate, looks at how some fish populations have collapsed within a matter of years. In Maine, the sea urchin became a popular commodity in Japanese sushi markets in the mid-1980s: After peaking in 1993, the catches declined precipitously.

The paper, authored by 15 Canadian, Australian, U.S., Swedish and Dutch ecologists, social scientists and resource economists, concludes that even marine protected areas such as the Great Barrier Reef Marine Park, the largest marine protected area in the world, "is too small to fully maintain stocks of marine mammals, turtles and sharks that migrate across its boundaries."

CONTINUED     1        >

© 2006 The Washington Post Company