Rolling grains of sand hit each other "like billiard balls, " said Kirby, and briefly fly into the air.
沙砾“像桌球”一样互相撞击翻滚，然后被风吹到空气中。
2
Instead, it secretes a glue and USES this to stick bits of sand together to form its casing, in the way that a freshwater caddis fly larva does.
堆沙蠕虫分泌出一种胶状物将沙石粘合在一起形成壳装，这一点类似于淡水石蛾的幼虫。
3
It took photographer Joel Sartore three months to get the permit required to capture, photograph, and release a single fly from its threatened sand dune habitat in California.