In the Sonoran Desert of southern Arizona, the western diamond-backed rattlesnake takes on a unique behavior to combat its extreme arid environment. Every so often, the serpent emerges from its rock-structured den and fixes itself into a flat, tight coil to collect rain, sleet, and snow – precious precipitation that it might otherwise miss.
But how exactly does the rattlesnake’s special body help facilitate this behavior, and why haven’t other snakes been observed displaying similar life-saving mechanisms? That’s exactly what researchers at Arizona State University set out to determine. First, it was apparent that a rattlesnake forms its body in a particularly strategic position.
“Regardless of the physical state of the collected water, these snakes are reported to flatten (dorsoventral flattening) their bodies considerably and at times form a tight coil for rain harvesting, presumably to enhance the collection of rain droplets,” write the authors in the journal ACS Omega.
“As the rain droplets accumulate and coalesce on the dorsal scales (with diameters of up to about 5 millimeters), the snake proceeds to drink the water from various areas on its body.”
It is the snake’s specially designed body that allows it to do so. From the perspective of “surface science,” scientists scanned the rattlesnake scales using electron microscopy – a technique used to obtain high-resolution images – in order to closely watch the moment of impact between a water droplet and the animal’s back. Images revealed tiny channels that form a “labyrinth-like network” – unique to the rattlesnake and not observed in either of the control snake species, the desert kingsnake and the Sonoran gopher snake. Dorsal scales help to collect water by providing a “sticky, hydrophobic surface” that pins water droplets to the surface. Once there is enough water collected, a snake will slurp the liquid down in much the same way it would from any other water source, be it a pond or a doggie bowl.
Though this particular specialized mechanism is unique to rattlesnakes, other desert-dwelling species have evolved similar techniques to hydrate in dry climates. Some lizard species found in the arid deserts and scrublands of Australia use their skin as a “web of drinking straws” that allows the reptile to use its feet to soak up dew from sand and sediment. Stenocara gracilipes, a species of beetle native to Africa’s Namib Desert, has evolved the ability to catch fog on its specially equipped wings that the insect will then roll down its back and into its mouth.
And you thought your reusable straw was clever.