A few years ago, scientists observed that some bottle-nosed dolphins held sponges in their beaks as they poked around the ocean floor, flushing out fish they promptly gobbled up—and that mothers taught this trick to their daughters. In a follow-up study published yesterday, the scientists shed some light on why dolphins go to all this trouble: They’re after fatty, energy-rich fish on the seafloor, and the sponges let them scare up a snack without scraping their beaks on sharp rocks or coral.

[PLoS One via ScienceNOW]