Amphibians are not necessarily known for their architectural acumen, but a new study shows that during the driest parts of the year some frogs take advantage the moist habitat offered by a ball of elephant poop.  Last fall, ecologist Ahimsa Campos-Arceiz of The University of Tokyo was checking out Asian elephant dung piles near Bundala National Park in Sri Lanka.  He was surprised to find a tiny frog-like toad in the genus Microhyla buried inside the twig-filled dung.  He kept snooping around, examining a total of 290 dung piles and found four more Microhyla along with a frog species.  By contrast, when he checked out cow and buffalo patties in the area, he never found any toads, a fact he attributes to the bovine dung’s “homogenous, fine-grained” structure.  His study, titled “Shit happens (to be useful)!  Use of elephant dung as habitat by amphibians,” will be published in Biotropica.  He says the finding demonstrates the role that large mammals like elephants play as “ecosystem engineers” providing resources and habitat to much smaller animals.