Discover: The eerie smarts of dog vomit and other fascinating slime mold facts

It oozes across a miniature landscape, searching and sifting for sustenance. The life-form possesses no brain or central nervous system, but it displays an eerie facsimile of intelligence, even demonstrating an ability to remember and anticipate events. 

You may have seen it in the leaf litter or on a decaying log without recognizing it; it’s found around the world and here in Ontario. It is Physarum polycephalum, the many-headed slime mold, and it’s a prime example of the amazing kinds of life hiding in plain sight all around us.

The term ‘slime mold’ itself is a slippery one; it describes a grab bag of organisms that have a similar way of life rather than a shared evolutionary heritage. What makes slime molds special is the double life they lead. They can live as microscopic, free-living individuals or can join together to form a large, collective organism. 

The way they join together differs, but in the case of the many-headed slime mold, the tiny individuals meld to form what is essentially one giant cell, called a plasmodium. This plasmodium, which can grow larger than a frisbee, oozes across decaying logs and damp forest floors at one cm/hour, sending out tendrils and engulfing food like bacteria and fungi. 

If you’re imagining something that could be from a science fiction B-movie, you’re on the right track. 

To the slime mold, the plasmodium state is important for forming the spores that will disperse across the landscape to make more slime molds. To scientists, the plasmodium state is important for studying some remarkable slime mold party tricks. 

When placed in a maze containing food — it’s particularly fond of oat flakes — the many-headed slime mold can determine the shortest path between its starting point and the food. It does this via a brute force, yet highly effective, approach: it sends out tendrils to populate every possible pathway through the maze and then it retracts the ones taking all but the shortest pathways. 

This method has inspired algorithms for path-finding tasks like optimizing road navigation. Something to think about the next time you’re using Google Maps.

Perhaps even more impressively, the many-headed slime mold appears to remember and anticipate events … despite not having a brain. When subjected to regularly occurring drops in humidity in a lab, for example, the plasmodium begins to anticipate the upcoming dryness, changing its behaviour. 

To top it all off, the many-headed slime mold has another trick up its tendril. When subjected to poor environmental conditions — like a long bout of dryness — the many-headed slime mold enters a state of suspended animation. It can safely stay in this hardened state for years until conditions improve.

The many-headed slime mold is just one of several species of slime mold you can find when hiking around Sudbury. To name just a few, we also have the charmingly named “dog vomit slime mold” (Fuligo septica), the oddly named “wolf’s milk” (Lycogala epidendrum), and the deceivingly named — at least in terms of taste — “red raspberry” (Tubifera ferruginosa) and “carnival candy cane slime molds” (Arcyria denudata). Each one successfully lives a double-life as an individual and then as a merged, collective organism. 

All of these slime molds, with their fantastical names, crayon-like colours, and strange-to-us life cycles, can be easily found in our backyards and local parks if we keep our eyes-peeled. Lake Laurentian Conservation Area and Killarney Provincial Park are two particularly great spots for slime mold spotting. The next time you see a splash of vibrant yellow, pink, or red in the underbrush, take a closer look, snap a photo, and tell your friends about this truly amazing kind of life.

Tobias Mankis is a freelance writer in Greater Sudbury.