Really smart slime.

• Position: Biology - Physarum polycephalum's food habits - Brief article

Slime gets a bad rap. It may conjure up images of Nickelodeon's celebrity slimings or the news last spring that some school lunch meats were filled with a type of "pink slime." But physarum polycephalum--a slime mold that lives in forests around the world--is actually pretty smart. When the mold looks for food, it emits slime that, remarkably, creates the most efficient path to that food. That got researchers wondering, just how smart is this slime? As smart as, say, the engineers who designed the U.S. Interstate Highway System in the 1950s? To find out, they used a dish shaped like the U.S. and placed pieces of rolled oats on 20 cities and a piece of mold on New York. The result: The network the mold created to connect the cities with its slime was very...