How could a slime mold be intelligent? After all, it’s only a single-celled organism. It could not possibly have a brain. (See photo: one slime mold cell. The branches are tendril-like extensions of the cell, called pseudopodia or “false feet.”)
However, it has been scientifically proven that slime molds are not stupid. They can find food and efficiently consume it with mathematical precision.
When a slime mold (such as the pictured Physarum polycephalum) needs nutrition, it extends its pseudopodia until it reaches food. The pseudopodia act like transport tubes to exchange nutrients from the food to the rest of the slime mold. The slime mold is able to find food and survive.
The next proof of intelligence comes from a Japanese research team’s experiment with slime mold in a maze. They put slime mold food (oat flakes) on one end of a small maze, and then placed the mold on the other side. The slime grew its pseudopodia until it covered the entire maze. Then it found the food, and this is where surprising results showed.
If a pseudopod was at a dead end in the maze and didn’t lead to a oat flake, it began to shrink and die off, leaving a thicker connection to the food source. And, if there were multiple pathways to the food, the slime mold almost always chose the shortest distance in the maze, getting nutrients in the quickest and most efficient way possible. The single-celled slime appeared to form its transport tubes purposefully, choosing which directions to build up and nourish based on potential food consumption.
Slime mold intelligence has been utilized in several interesting ways.
A slime can figure out the most efficient way to plan a subway system. Using the maze example, the oat flakes would represent people, and the pseudopodia are the subway lines.
A slime can also be used inside a computer chip by coaxing the slime through different gateways using food or the absence of food. See this quick lesson in Boolean logic – a “1” represents a pseudopod and a “0” represents an absence of a pseudopod.
Slime molds may not be geniuses, but they have evolved to become experts in traffic management and Boolean computing. Can you think of any other uses for this slimy intelligence?
Toshiyuki Nakagaki, Hiroyasu Yamada, Agota Toth: Maze-solving-by-an-amoeboid-organism http://www.imaginationstationtoledo.org/content/wp-content/uploads/2010/08/Maze-solving-by-an-amoeboid-organism.pdf
Discover Magazine: Brainless Slime Mold Builds a Replica Tokyo Subway http://blogs.discovermagazine.com/80beats/2010/01/22/brainless-slime-mold-builds-a-replica-tokyo-subway/
How Stuff Works: Simple Gates http://computer.howstuffworks.com/boolean1.htm
Mycelium Running: How Mushrooms Can Help Save the World by Paul Stamets (2005)
Stamets is a world-renowned fungi expert with lots of good information and discoveries to share about fungus, mushrooms, and of course their cousins the slime molds. I highly recommend either reading his books or listening to one of his lectures (http://www.ted.com/talks/paul_stamets_on_6_ways_mushrooms_can_save_the_world.html) if you are interested in how fungi act inside biology and ecosystems.