When you're a male gator looking for a mate, you don't need a dance floor to make all the right moves; the warm waters of the Everglades will do just fine, as shown in this National Geographic video.
Male alligators turn on some nifty waterworks to woo their mates. Their backs vibrate beneath the swamp surface, sending columns of water shooting up like a fountain, while the gators punctuate the display with booming bellows. It turns out that this is no ordinary splash: The vibrations and booms create Faraday waves in the water — special oscillations that are not usually found in nature.
Peter Moriarty, a mechanical engineering major at Boston University, spilled some of the secrets of the Florida swamp at the Acoustical Society of America's annual meeting in Seattle last week.
During a trip to the Gatorama alligator farm in Fort Myers, Fla., Moriarty observed the wobblings and warblings of two bull alligators, nicknamed Goliath and Mr. Chicken. He recorded their bellows and water displays, and played back audio tracks to see how they'd respond.
When Moriarty analyzed the recordings, he found that the gator waves had the signature frequency of Faraday waves.
Faraday waves don't just create a fancy water display — they also travel long distances. Even though people can't hear these subsonic vibrations, they can feel them from far away. "You could be 50 feet from an animal and feel the vibrations up your leg. It’s very powerful," said Kent Vliet, coordinator of zoology labs at the University of Florida, who's worked with crocodilians for several years.
Because low-frequency Faraday waves travel so well through water, it makes sense that swamp-living alligators use them to make contact with mates over long distances. "Perhaps the [alligators] that make Faraday waves better would propagate more effectively," Moriarty said.
Next, Moriarty will study the structure of an alligator's armor, to see if there's something about the shape, size or spacing of the protrusions on the back that helps some gators create fitter Faraday waves than others.
More on curious courtship from the Cosmic Log:
- Skewed sex ratio curbs courtship
- Urine spray signals sex, violence to crayfish
- New tunes, not oldies, lure the ladies