There’s a brand new organism on display at Le Parc Zoologique de Paris,
one that just might win the title of strangest thing in a zoo EVER.
Because it’s not an animal.
It has no eyes, ears, mouth, or limbs,
but it is mobile, it can communicate,
it can heal itself and it has nearly 720 biological sexes.
It’s *drumroll please*...a slime mold.
Affectionately called by some scientists who study it: "le blob."
So what exactly is a slime mold?
While its name may lead you toward the fungal section of the tree of life,
slime molds are actually protists, belonging to the phylum Amoebozoa.
And there are actually two very different kinds of slime molds: cellular and acellular.
Cellular slime molds are tiny amoebas that require a microscope to see,
but they can clump together into a slimy blob that acts as one whole superorganism.
That’s why this kind of slime mold is sometimes called the social amoeba—
they like to get together and hang out sometimes under the right conditions.
But the one we’re talking about, the one now in the Paris Zoo, is an acellular slime mold
whose official name is Physarum polycephalum.
This organism still starts as an amoeba but as it continues to grow,
the nuclei divide, but the cell does not.
It essentially forms into one giant cell, called a plasmodium.
Like, this huge yellow moving thing is just one cell, like a giant bag full of lots and lots of nuclei.
And it moves its cytoplasm around in eerily vein-like structures,
which is actually teaching us quite a lot about cellular transport.
So understandably, scientists were pretty confused about how to classify slime molds for a long time.
Because like fungi, they have spores.
They start out as microscopic spores
before ballooning into the slime mold that we can see,
and when they get to a certain stage in their life cycle and when their environment becomes unfavorable,
they just go POOF, and disintegrate into spores again.
Kinda wish I could do that.
But unlike fungi, when they're eating they just swallow stuff whole,
instead of releasing enzymes that break stuff down outside their bodies.
And another key defining factor that separates slime molds from fungi
is that slime molds can really get around, like they are highly mobile,
while fungi are quite a bit more stationary.
And their adventurous nature is not all that makes them special.
Because slime molds are smart.
Studies have shown that social amoeba—those cellular slime molds—demonstrate agricultural behavior.
They eat bacteria, but instead of eating all the bacteria they find, they sometimes save some for later.
They carry that bacteria with them, and then they can plop it down and grow more of it
to eat in their new location and to provide for their offspring.
Slime molds are farmers, you guys!
Which is especially cool because neither cellular or acellular slime molds have brains.
And research has shown that acellular slime molds like the one nicknamed "le blob,"
demonstrate something like learning.
P. polycephalum slime molds can learn how to ignore uncomfortable but harmless chemicals
in order to access their food source.
This is a process known as habituation.
Those organisms can then retain that information during long periods of dormancy
and can pass on this knowledge to other slime molds that have never experienced
that unpleasant chemical before.
Or when a bunch of separate slime molds are cut up and then introduced to each other,
they form into one whole mass, which is already crazy.
But if just one of those pieces is from a slime mold that was habituated to the unpleasant chemical—
then the whole re-formed organism also knows the chemical isn’t harmful.
And we honestly don’t know how any of this works.
We don’t know the mechanism of action for this cognition,
and lots of very brain-centric researchers, like neuroscientists,
object to calling it cognition in the first place, so there’s still tons to explore here.
And just as icing on the slimy, yellow cake?
“Le blob” can have almost 720 sexes.
There is no male or female, just hundreds of different possible sex categories.
Because remember its ability to spore? Well, those spores are haploid.
That means each one contains only half of the necessary genetic information
to make a whole slime mold. And that's just like eggs and sperm in humans.
But slime mold spores carry one copy of three different possible sex genes,
and each of those genes can come in many different varieties.
So, when that haploid sex cell finds its other half,
the possibilities with all of those variables involved results in many hundreds of possible options
for the sex of the resulting organism.
So what’s the coolest part about slime molds to you?
Do you want us to cover more aspects of these guys in more detail?
Let us know down in the comments, and make sure to subscribe to keep up with more surprising slimy facts.
For more microbial magic check out this video on fungal networks over here,
and as always, thanks so much for watching. I’ll see you next time.