A creature with no brain can still leave a maze with a surprisingly tidy route.
Physarum polycephalum is a single-celled slime mold that spreads as a branching web of tubes. In a 2000 experiment, researchers placed food at two points in a maze and watched the organism extend through the passages. It eventually connected the food sources along the maze’s minimum-length route.
The result does not mean the slime mold thinks through a map as we do. Its living network changes as it grows, and the successful path remains while less useful extensions fade. That simple process can produce an elegant solution to a spatial challenge. The experiment gave scientists a way to study how a network might adapt without a central commander.