Monday, August 28, 2006

Trap-Jaw Ant's Bite Sets Record

A species of ant found in Central and South America has become the new record-holder for the fastest jaws in the animal kingdom.

The trap-jaw ant ( Odontomachus bauri ) can snap its mandibles closed in less than a millisecond, at speeds reaching 145 mph -- moving 2,300 times faster than the blink of an eye -- the fastest bite ever recorded, according to new research.

High-speed-video studies of trap-jaw ants collected in Costa Rica show the insects' jaws generate forces exceeding 300 times the tiny creatures' body weight.

"The mandibles are operating in the outer known limits in biology in terms of speed and acceleration," said Sheila Patek of the University of California at Berkeley, whose team published the findings in the Aug. 21 issue of the Proceedings of the National Academy of Sciences.

The ants use their phenomenal jaws not only to catch prey such as other ants and termites but also to launch themselves in the air to escape predators, such as spiders, frogs and lizards, the researchers found.

The force of their jaws, powered by a large head filled with muscle, can propel them to heights of up to 3 inches and horizontal distances of up to 15 inches.

When the ants are in groups they sometimes use their jaws to escape in unison, creating a "popcorn effect" that, the researchers speculated, may confuse predators.

-- Rob Stein

Fresh Water Diluting the Seas?

A rising amount of fresh water flowing into the Arctic Ocean from rivers, ice melt and precipitation may account for the decreasing saltiness of the North Atlantic over the past 50 years, according to research published Friday in the journal Science.

Scientists from Woods Hole Oceanographic Institution, the University of Texas at Austin and other research centers compared freshwater trends in the Arctic with those in the North Atlantic over the past half century and found that they matched.

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