Dolphins gossip, biologists discover

Question: What's a most surprising thing dolphins do when they get together? People do it, too, behind each other's back, as do magazines and TV shows to the point where it may bring down a president or a prime minister. If you thought dolphins above this sort of behavior, think again. So what are the Flippers of the world up to?

Answer: They gossip, reports a team of Scottish marine biologists. Amazingly, each bottlenose dolphin identifies itself with a unique series of clicks and whistles along the lines of Woo-woo-wee-wee or even Woo-woo-wee-woo-wee-woo, says Bruno Maddox in "Discover."

This has long been known, but what the researchers uncovered is that two clicking and whistling bottlenecks will at times use the name of a third dolphin when it is not present.

"For those of us who've been led to believe dolphins are a higher order of being — honorable and enlightened, Gandhis with blowholes — their gossiping came as something of a blow to the stomach."

Question: That annoying co-ed next to you in science class keeps cracking her knuckles, until she's knuckled out. For an "A" in anatomy, what's behind the cracking sounds, and why the periodic respites?

Answer: Pull on a finger with enough force and the knuckle cavity (space between bones) widens, reducing the pressure on the synovial fluid inside, says Jearl Walker in "The Flying Circus of Physics."

Now gas bubbles may suddenly form, primarily carbon dioxide, that had been dissolved in the fluid. This "cavitation" sends a pressure pulse through the fluid, the knuckle cavity, and out into the air. End of show — for now. It will take 15-30 minutes for the cavity to recover its initial shape, as the fluid is squeezed back to a thin layer between the bones and the gas redissolved into the fluid.

"Until then, she will need some other bad habit to annoy the people around her."

Question: That microphone hidden in a shrub along the roadway — what's it doing there? Clue: Think Fuzzbuster-buster.

Answer: Police may use it to gauge the "Doppler shift" (change in pitch) of your car's noise as you drive by, says NewScientist magazine. The ace in this speed-enforcement game is that unlike radar or laser-based devices, the system emits no telltale radiation and so cannot be picked up by dashboard detectors.

When University of Tennessee researchers tested this, they could determine speeds to within a few percent in 32 of 33 experiments.

Plus, the engine's pulsing sound gives away the rotations per minute, an acoustic tip-off to approximate engine size. With microphones installed along calibrated roadway slopes, police can monitor a truck's increased power expenditure, allowing calculation of vehicle weight and whether the truck is overloaded.

Some sound science in service of snoopability.

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Send STRANGE questions to brothers Bill and Rich at strangetrue@compuserve.com, coauthors of "Can a Guy Get Pregnant? Scientific Answers to Everyday (and Not-So- Everyday) Questions," from Pi Press.