At 3,000 years old, Tasmania’s Huon Pine has seen its share of history. If this towering tree were ever asked the secret to its longevity (provided it could speak), it most likely would answer, “You are what you eat.” And in the case of the Huon Pine, that would be a steady diet of some of the Earth’s purest soil which gets supercharged by physarum polycephalum—universally known as “slime mould.”
Slime Mould? Sounds gross, right? Well, not nearly as gross as its more common nicknames dog vomit, demon droppings, witch’s butter and caca de luna (moon s***). But what is this soil steroid? The answers will shock you.
ANIMAL? VEGETABLE? ALIEN?
What is slime mould? That’s a question that biologists have been trying to decipher for centuries. In fact, if there ever was a prize given to the organism with the biggest identity crisis, slime mould would easily win.
Back when all living things were placed into two kingdoms – animals and plants, slime mould was considered the latter. It was later moved into the kingdom fungi. As it was studied further, its pulsating feeding stage moved it to the animal kingdom. After its single-celled amoeboid feeding was observed, it was recategorized in the kingdom protozoa. This seemed to work for scientists until they remarked that slime mould has an amoeboid, plasmodial and spore-bearing stage. Now, it is considered to be Amoebzoan.
There are over 900 species of slime moulds on every continent. They can grow on just about anything organic but thrive in dark, cool moist conditions like forest floors where they can feast on an array of bacteria, yeast, molds and various fungi. Tasmania’s Thismia Gully, Big Tree Track and Black Sugarloaf regions provide ideal conditions for a wide variety of slime moulds.
GROSS, BUT HELPFUL
When you look at a sample of slime mould, it resembles a blob (or as Tassies say, “dog poo”) But that poo is actually countless amounts of smaller single cells that have merged into a large food-seeking machine. Once a slime mould has exhausted its food, it can go dormant and break up into hundreds of thousands of spores that can re-group to feed elsewhere. If that sounds a bit scare, it’s not – unless you’re the bacteria, single-celled fungi or yeast that the slime mould is aiming to eat.
To the rest of the animal and plant kingdoms, slime mould are not toxic, poisonous or venomous – in fact, they help build up sandy soils by returning nutrients. So, when you see a particularly large or gross clump of slime mould on your lawn or in garden mulch, don’t be taken aback. It’s not an alien. It’s just a whole lot of cellular buddies working together to decompose organic matter – they just do it in a very unsightly manner. When they’ve done their job, it will dry up and its millions of spores blow away and regroup elsewhere. (“Our work here is done!”)
But while its helpful for your garden to occasionally have slime mould, we understand that it’s far from appetizing to have in abundance if you’ve got company coming over for a backyard barbecue. So, if you’ve got an outbreak on your lawn, you can quickly get rid of it with a garden hose or lawnmower. If it’s in your flower bed, you can scoop it up and bury it. Don’t worry. It doesn’t bite!
SMARTER THAN THE AVERAGE AMOEBA
Even though a sample of slime mould is actually a collective of millions of microscopic organisms without a central nervous system, when in search of food, it can display behavior that resembles intelligence.
Much of the research done on slime mould has been conducted in Japan. In fact, Emperor Hirohito (a biologist himself) loved slime moulds and is even credited with discovering new species. And while we know little of how the organism behaves in the wild, Japanese research has turned up some really surprising findings on what it’s able to do in a lab.
An experiment conducted at Hokkaido University found that a sample of slime mould could find the minimum-length between start and end points of a maze. Another experiment with slime mould saw a sample of slime mould replicate Tokyo’s suburban rail system by linking oat flakes on a dish that were set up like rail stations.
EIGHT SURPRISING FACTS ABOUT SLIME MOULD
While slime moulds aren’t sentient beings, they are able to do some really amazing things without a brain or central nervous system. Long-running PBS series NOVA outlined eight really amazing things that slime moulds are able to accomplish in their pursuit of food.
1 – They Can ‘Smell’ – The receptors in a slime mould’s cell body can detect chemical cues from food nearby.
2 – They Can Pulsate – In its pursuit of food, slime moulds set up a network of “veins” to travel to their next meal.
3 – They Can Navigate – the shortest distance between two meals can be mapped by a slime mould.
4 – They Can Reunite – Cut it in half or shred it, a slime mould can reform if torn apart.
5 – They Can Make Smart Food Choices – A study found that given the option between sugar and salt, moulds stayed away from salt.
6 – They ‘Remember’ – Slime mould can retrace their steps by leaving behind little ‘breadcrumbs’ in the form of slime.
7 – They Adapt – More advanced species of slime moulds are capable of habituation. They can get used to difficult things in their environment if rewarded for it.
8 – They Can Teach – When a slime mould that has ‘learned’ to tolerate salt fuses with another slime mould, the expanded organism can also adapt.
Ready to nerd-out with further Slime Mould reading and viewing? Visit our sources:
EIGHT SMART THINGS SLIME MOLDS CAN DO WITHOUT A BRAIN – https://www.pbs.org/wgbh/nova/article/slime-mold-smart-brainless-cognition/
THE EMPEROR’S LOVE OF SLIME MOLD – https://www.popsci.com/emperors-love-slime-mold/
SLIME MOLD MAY LOOK LIKE DOG VOMIT BUT ITS BENEFICIAL IN YOUR LANDSCAPE – https://www.tcpalm.com/story/life/columnists/carol-cloud-bailey/2019/04/07/slime-mold-beneficial-your-treasure-coast-landscape-garden/3266678002/
SLIME MOULDS – BIOLOGICAL JEWELS OF NATURE – https://sarahlloydmyxos.wordpress.com
THIS BRAINLESS BLOB LEARNS AND TEACHES TOO – https://www.livescience.com/57360-brainless-slime-mold-learns-and-teaches.html
SLIME MOLD SOLVES MAZES – https://www.youtube.com/watch?v=eXeygGxu8-8&feature=emb_logo