On the horizon


Do mice squeak ... or sing?

It may not sound like "Moonlight Serenade," but a serenade it is. Male mice sing in the presence of females, say researchers at Washington University in St. Louis. Scientists have known for some time that male mice vocalize when females are around. These sounds take place above the range of human hearing. But analyzing them for structure has been tough, requiring powerful computers and improved recording technology to pull it off.

The team learned that male vocalizations fell into different categories of sound. And these sounds often came in themes or motifs the mice repeated as they sang. Next up? Answering the musical question: Do wild mice sing differently than lab mice?

The team's results appear in the latest issue of the Public Library of Science Biology.

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To slow a tsunami, use mangroves

Scientists have long suspected that healthy, dense mangrove forests can protect a coast from storm surges. Much of that is based on modeling studies. Now, evidence from last December's tsunami in the Indian Ocean appears to back up the models.

An international research team looked at a straight stretch of India's east coast - the Cuddalore District in Tamil Nadu, India. They found that villages built behind mangroves suffered little or no damage. Shoreline villages to the north and south were destroyed. Villages built within coastal plantations of Australian pine endured partial damage.

The team acknowledges that in places where the tsunami was most intense, little could have been done to prevent the wave's destruction. Still, conserving or rebuilding "greenbelts" along coastlines could go a long way toward sapping the strength of future tsunamis, the group reports in the current issue of the journal Science.

A volcano's impact on sea levels

When Mt. Pinatubo erupted in 1991, the Philippine volcano spewed particles into the stratosphere that cooled the planet for several years. Scientists now say the particles also limited the amount of solar radiation reaching the ocean, reducing the amount of heat and lowering sea levels.

Modeling studies and real-world measurements of ocean heat content conducted by a team of US and Australian scientists indicate that the ocean's recovery from the effects of Mt. Pinatubo accounts for about half the increase in the rate of sea-level rise from 1993 to 2000. The other half was attributed to melting glaciers and ice sheets, the team reports in Thursday's issue of the journal Nature.

Under development: gecko glue

Scientists have moved a step closer to understanding why geckos can climb walls, walk upside down across ceilings, and perform other feats of adhering do. Tiny pads on their feet, called spatulae, do the clinging and appear to need a certain level of moisture on the surface to pull off their stunts.

Gecko adhesion is a hot topic in materials science because it holds the promise for developing new kinds of adhesives for human use. A team of German scientists plucked some of these pads (no mean feat, since they are about 200 billionths of a meter wide and long), then tested the amount of force needed to pull the spatulae off different surfaces. The force required rose with the surface's affinity for retaining microscopic amounts of water. It also rose with the amount of humidity in the air.

The results appear in this week's issue of the journal Proceedings of the National Academies of Science.

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