The plasmodium of the slime mould Physarum polycephalum is a large amoeba-like cell consisting of a dendritic network of tube-like structures (pseudopodia). It changes its shape as it crawls over a plain agar gel and, if food is placed at two different points, it will put out pseudopodia that connect the two food sources. Here we show that this simple organism has the ability to find the minimum-length solution between two points in a labyrinth.

1. Bio-Mimetic Control Research Center, RIKEN, Shimoshidami, Moriyama, Nagoya 463-0003 , Japan
2. Local Spatio-Temporal Functions Laboratory, RIKEN, Wako 351-0198, Japan
3. Research Institute for Electronic Science, Hokkaido University, Sapporo 060-0812, Japan
4. Department of Physical Chemistry, University of Szeged, PO Box 105, Szeged H-6701, Hungary

Correspondence to: Toshiyuki Nakagaki^1,2 e-mail: Email: nakagaki@postman.riken.go.jp