Here’s Another MNN headline that caught my attention: “Can 3-D printing save homeless crabs?” The crustaceans or crotchety people? The former, it turns out. Hermit crabs—any of 1,100 species in the superfamily Paguroidea—are not born with their own shells; they must scavenge discarded shells, typically those left by sea snails. (The end of the hermit crab’s tail has adapted to fit sea snail shells.) As the crab grows, it needs to find larger quarters. Discarded gastropod shells are a limited resource, so competition amongst hermit crabs has tended to be fierce. (In a pinch, though, hermit crabs are perhaps the McGyvers of the sea: they can often make use of empty beer bottles, shotgun shells, or any other suitably shaped object. As of late, however, researchers have discovered that hermit crabs are facing a housing shortage—no, the banks are not foreclosing on their shells, but rather a combination of seashell collection and ocean acidification (which threatens the beshelled gastropods) is making suitable shells more and more scarce. Enter Project Shellter, and MakerBot Industries, a New York-based company that develops 3-D printers, specifically the Thing-O-Matic (not to be confused with the ThingMaker, a toy many of us had in the 1970s that made Creepy Crawlers). The Thing-O-Matic uses digital “blueprints” to carve plastic objects—sort of a CAD/CAM application. The company is working with marine biologists and designers to crowdsource suitable hermit shell designs and thus produce plastic shells for homeless crabs. In several “crabitats,” MakerBot and co. are testing out designs to see which ones the crabs actually like. Hermit crabs, as scavengers, play an important role in their ecosystems, and anything that threatens them threatens those ecosystems.