As a kid on superhot days on Southern California beaches with no go-aheads on feet, The Tracker learned one could shuffle along – laboriously – without pain by keeping tootsies in the cooler sand just under the surface. Now Georgia Tech researchers report, in a cute account in Science, that the Saharan sandfish has raised that subsurface travel concept to a high art. It dives entirely under the sand – nothing new there, it is how the animal got its name. More important to animal kinesiology fans, infrared, sand-penetrating imagery shows that it propels itself without using its legs much, if at all. Rather, it swims, undulating a bit like a snake. Its head waves back and forth and a big “traveling wave” sinuates at near-fixed amplitude down its whole, smoothly-scaled length.

It’s only four inches long but not exactly a cute li’l critter – long pointy nose, countersunk jaw, flat sides – but weird animal stories are hard to resist, too. Nobody writes it very long – there really isn’t much more to say than wow get a load of this. Most stories use the possibly-practical application of such work to robotic versions of the lizards.

At Physics World, with a readership that might want to know a lot more, editor Hamish Johnston wrote it up lickey split on line, and with a nifty hed: Physicists spy on skink swimming through sand. Just enough alliteration, not too strained (one could have overdone it, smuggling in subterranean, slinking, slithering, or serpentine), and good to know this lizard is a skink.  We also learn that earlier, MRI studies implied they do use their legs.

Other Stories:

• USA Today – Dan Vergano : Lizards swim through sand ;  He says it swims “just like fish through water,” and it does look a lot like a fish. But hmmm – the study reports that the closest resemblance is to eels, but eels expand the amplitude of the traveling wave as it goes nose to tail. So maybe it’s not just like a fish.
• LiveScience : Through sand, desert lizard swims like a snake;
• NYTimes – Henry Fountain: Saharan Lizard Swims Through Sand ; Fountain does a good job explaining why it goes just as fast in dense, compacted sand as in fluffier stuff. It has to do with a constant drag and thrust ratio (it’s probably working harder in the dense material but that’s for further study to say).
• Scientific American – Katherine Harmon: A lizard that swims through sand ; Supershort – more of a fat caption linked to the video.
• ANI (via New Kerala, India): Sandfish tucks legs and swims like  a snake through desert sand ;

Grist for the Mill: Ga. Tech. Press Release ; Video ;

This entry was posted on Friday, July 17th, 2009 at 11:35 am and is filed under Science Stories. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.