THE United States interstate highway system is often celebrated as a simple yet highly efficient transportation scheme — one that, starting in the 1950s, transformed the American economy and lifestyle. Its network of roads was designed to maximally span the country with a minimal number of links, while still allowing for enough redundancy to help drivers overcome wrong turns and missed exits.

But it’s worth remembering that the highway system was created by mere humans, using only human intelligence. To find out if it’s optimally designed, we need to consult a higher authority. Namely, slime mold.

Let us explain.

There is a slime mold known as Physarum polycephalum that lives in forests around the world. It feeds on various kinds of microscopic particles. As it forages for food, protoplasmic tubes of slime extend out and bifurcate like tree branches; whenever it happens upon a source of nutrients, it gathers into a bloblike formation. The whole thing — blobs connected by tubes — is a single organism, and the network serves to transport nutrients throughout its “body.”

An interesting fact about this slime mold is that it is highly intelligent — or at least it behaves as if it is. In locating food in its environment, it builds networks that have been shown to be optimally efficient in transporting the nutrients over the area in question. If placed in a maze, for instance, with a source of food outside the maze, the slime mold will discover the shortest path out.