Wolf’s Milk Slime Mold – The Consummate Shape Shifter

There was something strange outside.  I mean, there was something REALLY weird outside.  It was out near the barn on an old log and looked like this:

What was it?

What was it?

It was between 3 and 4 inches long.  And it gave me the creeps…it was really disgusting looking.  It must be some weird fungus, I thought.  So I headed inside to do some research.  Fungi…there are so many different types of fungi.  I looked at hundreds of images and then finally, I saw one that looked similar.  But it turned out not to be a fungus, it was a slime mold.  A Wolf’s Milk Slime Mold to be exact.

According to Wikipedia:  “Lycogala epidendrum, commonly know as wolf’s milk, groening’s slime is a cosmopolitan species of plasmodial slime mould which is often mistaken for a fungus, The aethalia, or fruiting bodies, occur either scattered or in groups on damp rotten wood, especially on large logs, from June to November.  These aethalia are small, pink to brown cushion-like globs.  They may excrete a pink paste if the outer wall is broken before maturity.  When mature, the color tends to become more brownish.  When not fruiting, single celled individuals move about as very small, red amoeba-like organisms called plasmodia, masses of protoplasm that engulf bacteria, fungal and plant spores, protozoa and particles of non-living organic matter through phagocytosis.

“During the plasmodial stage, individuals are reddish in color, but these are almost never seen.When conditions change, the individuals aggregate by means of chemical signaling to form an aethalium, or fruiting body.  … Colour is quite variable, ranging from pinkish-grey to yellowish-brown or greenish-black, with mature individuals tending toward the darker end.”

This info came from mdc.mo.gov:  “Though it may seem like one, this species isn’t actually a mushroom or fungus.  It belongs to a group called slime molds, or myxomycetes – a group of funguslike organisms that at one time were regarded as animals, then thought to be plants, then fungi.  Now, because of DNA studies, slime molds are believed to be closer to the protozoa.  They are studied by botanists and mycologists….  They have two life-cycle stages.  The first, “plasmodium” stage is rarely noticed.  It is like a huge, single-celled amoeba that creeps on dead plant material in long thin strands, engulfing and digesting bacteria, yeasts, and fungi.  When ready to reproduce, it enters into its funguslike “sporangia” stage, which makes spores that float away to became new plasmodia elsewhere.”

This slime was originally thought to be an animal (it moves!!!), then a plant, then a fungus.  Now believed to be closer to a protozoa!  And it’s right here in my backyard.  It no longer seemed so disgusting to me.  It was amazing!

The mushroomexpert.com says that the Plasmodium state is “the creepy stage.  Like something out of a B-movie. The slime mold plasmodium is a mass of glistening veinlike material that creeps across dead leaves or wood at the  rate of as much as an inch per hour, growing, eating, and probably doing other nasty things we don’t evenwant to know about.  There are no cell walls in the plasmodium, and its motion is the result of protoplasm flowing rhythmically through the organism.”  Fascinating!

I kept reading and learned that it moved toward food and fled from harm.  And sunlight was harmful to it.  Uh, oh…I think the sunlight was moving in on my slime.  I ran outside to see, and sure enough, there was dappled sunlight on it.  I stood there with my shadow providing relief to the slime.  I had to move it somewhere with relatively no sunlight.  And that would be near the woodpile.  So it was moved. 

And as I looked at my slime in its new spot, I noticed some bright red dots on another piece of wood.  Wow, this must be the plasmodial stage that is rarely seen!  A photo follows:

Plasmodial Stage

Plasmodial Stage

I went out this morning to check on my slime…to see if it was happy in its new spot.  And it looks very pleased with its new surroundings: 

Mature Wolf's Milk Slime

Mature Wolf’s Milk Slime

But the bright red plasmodial dots have moved elsewhere…I looked and looked and they are nowhere to be found.  I’m glad I got that photo when I did.

Following are two posts that you might find entertaining:


A group of biologists in 2009 studied the slime-mold species Physarum polycephalum, a gelatinous, single-celled organism resembling a fungus. The researchers drew a figure of downtown Tokyo (the yellow dot in the slide below) close to the ocean (the white outline), surrounded by other urban centers (white dots). They placed the slime mold in downtown Tokyo and yummy slime-mold food (oat flakes) in surrounding areas. Then they waited.

After five hours the slime mold had explored the area immediately around Tokyo, extending its tendrils systematically and randomly in all directions. After eleven hours it had ventured farther, favoring some routes and closing down others that proved to be dead ends. After twenty-six hours it had resolved its myriad pathways into just a few highly efficient ones:

The slime mold was solving a problem that continually challenges subway system designers: how to find the quickest routes between separate destinations in a transportation system. And the slime mold was doing it all without the benefit of a brain. (So what are our brains for, anyway?)

How does the slime mold accomplish its design miracle? It self-organizes, communicating moment to moment among its constituent parts. Ed Yong at the Guardian explains in more detail:

The plasmodium is a single sac but it behaves like a colony. Every part rhythmically expands and contracts, pushing around the fluid inside. If one part of the plasmodium touches something attractive, like food, it pulses more quickly and widens. If another part meets something repulsive, like light, it pulses more slowly and shrinks. By adding up all of these effects, the plasmodium flows in the best possible direction without a single conscious thought. It is the ultimate in crowdsourcing.

More recently, researchers have found that the tissue structure of the slime mold resembles that of animals—animals usually thought of as “more sophisticated” than slime mold. Moreover, the slime mold accomplishes its cellular self-organizing using two proteins that are similar to those used by animals to organize their own cells

The Tokyo subway study was published in Science in early 2010. Its lead author, Atsushi Tero of Hokkaido University, believes that studying how the slime mold solves complex design problems could help urban planners solve theirs. He has even developed a computer model of the slime mold’s decision making and set it loose on a map of the United States, published in Popular Science.

Paul Stamets adds his thoughts on the Tokyo experiment:

Is it true that these cellular networks are actually intelligent? … When mathematical analysis was applied, they found something astonishing. The mycelium, given these different options, optimized mathematically, making the best possible design that engineers could come up with.

He concludes,

So if you have an engineering hurdle, perhaps you should ask a slime mold!”

And this lovely post (Lessons of a Slime Whisperer) came from Justine Riekena:


“Slime molds (or slime moulds) are simply spectacular creatures. Once classified among the fungi, slime molds have been more recently re-assigned to the grab-bag group Protista, in part because they have mobile, animal-like forms during their life-cycle. There are many varieties of slimes, but they can be very generally categorized into two groups. The plasmodial slime molds, in their motile stage, basically behave like an enormous (that is, visible to the eye), single-celled organism. But being a crawling, king-sized cell is not enough for our oozing evolutionary overachievers. These jumbo masses of ambulatory protoplasm, these ‘giant cells’ contain not one, but literally thousands of nuclei. Oooh, just think about that. Equally as impressive are the cellular slime molds who live as sovereign, single-celled protists until conditions get tough. When the solo cells begin starving, they engage in a phenomenon called chemotaxis. Releasing a chemical signal into their environs, they incite all their neighbors to gather en masse into a multicellular swarm — a swarm that behaves as a single organism. Over one hundred thousand individuals can come together as a communal blob, a protistan Wild Hunt in search of more favorable conditions. Awesome. Slime molds are consummate shape-shifters. Their remarkably dynamic lives can be loosely divided into an “animal phase” and a “plant phase.” Like any good animal, during their animal phase they spend their time eating and growing. The cellular slimes do this as solitary, amoeba-like beasties while the plasmodial slimes busy themselves by crawling about in search of food in a slippery mass. During their plant phase slimes tap into their highly innovative generative talents. This involves transforming into one or more fruiting bodies that bear a striking resemblance to the fruiting bodies of many fungi (hence their long history of classification as the Myxomycophyta). Like fungi, they ‘flower,’ growing a stalk and cap-like structure where they produce spores. This is the slime mold’s pièce de résistance — an awe-inspiring burst of reproductive splendor and a sight to behold.

Still, why slimes? These creatures are so odd and obscure. Sometimes I speculate about the origins of my rapport with them, but these types of relationships are often enigmatic. I did not wake up one day feeling an urge to go seek out a slime mold for a spiritual exchange. Borrowing the words of an old friend, I liken it to connecting with patron deities: “We do not choose the gods. The gods choose us.” I believe this can be extended to other spiritual partners as well. They call upon us, sending us signs and signals in their own way. When I am out wandering, I make an effort to remain open to their cues. I will abruptly stop in my tracks and look towards something that I don’t yet see. Often, they clue me in by scent or sight, other times they whisper, or vibrate. More often than not, I feel their presence before I actually find them, as if I am being called upon, or watched. Like any other beings, if slimes want you to find them, they let you know.

As individuals, I consistently find that they have something to say. Like any other living creature, they vary in temperament and orientation. I do not feel a fondness for, nor even a comfort with every slime I encounter, but I greet them all. I have met many types; wispy and demure, brazen and haughty, occupied and goal-oriented, solitary, gregarious, breathtakingly beauteous and frightfully unappealing. On days when I am tethered indoors, I find myself gazing longingly out the window, wondering who is out there lurking in the rotting corners of the forest; wondering who has erupted in fruitful glory; wondering what lessons I will be missing. Whenever I can, I go to them and listen. I invariably take home a message. I also take a photo or two, to serve as a reminder of a friend who has taught me something and in all likelihood I will never see again.

As a group, slime molds offer us new perspectives on beauty and diversity. They take on a myriad of forms and colors, often unexpected and captivating, sometimes frumpy and dull, perhaps even a bit distasteful, but never disappointing. Like the hermaphrodite, they challenge our traditional labels, categories and conceptions. They sit among the biologically ambiguous. They ask us to consider our assumptions about life on Earth — what makes us animals? What makes a plant?

The slime molds often recall to me lines from Charles Bukowski’s, The Laughing Heart: “…the gods will offer you chances. know them. take them…” They tell us to take advantage of opportunities and persevere despite difficult conditions. Slimes know how to respond to uncertainty, to adapt quickly with finesse. They embrace possibilities and change with gusto. To meet them, you must go outside often, make yourself available, seize the day. Carpe diem: they do this to survive, we must do it to thrive. Slimes have much to tell us about being fully present in the moment, making the most out of the time we have, living fully in this life.

The incredulous will ask, ‘All this from some slimy goo that can’t decide if it is a plant or an animal?’ My answer is a resounding ‘Yes!’ about which I could elaborate ad nauseam. There is so much more beyond the range of this piece; like their talent for completing mazes, how they have inspired scientists, artists, filmmakers, game developers and why the Japanese consulted them on the expansion of Tokyo’s subway systems. Despite the cleverness of the crow and the wisdom of trees, I think the slime molds are the bee’s knees. They are the quirky oddballs of Mamma Nature’s nest and they have so much to reveal to us. If we are open to their lessons. What secrets will you find out there on the forest floor? … carpe diem my friends.”






One thought on “Wolf’s Milk Slime Mold – The Consummate Shape Shifter

  1. KerryCan

    As I read this, I alternated between being completely grossed out and queasy, on one hand, and fascinated, on the other. The slime is fascinating in itself but your research is what really amazes me! And your curiosity! I may have nightmares about advancing slime mold . . .


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