ABC Listen.
Hello, I'm Nidge.
And today on Imagine This, I'm following a trail.
A squiggly, slimy trail.
It looks all shiny.
Where is it leading?
Follow me.
This way.
No, this way.
Hang on, I'm going in circles.
This trail is all over the garden path.
They look like... I think I... They're snail trails.
Hey, look.
It's a snail.
Oh, hey, little critter.
You've been busy.
That's a long trail you left us.
Oh, it's gone inside the shell.
Yeah, I love the shape of a snail shell.
It's a swirl shape.
Swirly, whirly.
So pretty.
George has been wondering about snail shells.
Hi, my name is George and I'm eight years old and I want to know how the snails get their shells.
What do you think?
Maybe they grow it?
I think they find them.
Buy it from a shop?
Snail shell?
What if the snail grows and needs a bigger shell?
I think they turn into a slug.
We should ask the snail whisperers.
Do they whisper to snails?
Oh yeah.
Hi, have a nice shell.
Please stop eating our garden.
I love you snails.
Their names are Dr John and Dr Laurel Stanisic, and they're Australia's top experts on land snails.
Let's go talk to them and see what we can learn about snails and their shells.
Hi, Dr John.
Hi, Dr Laurel.
Hi.
Hello.
Hello.
Hello.
G'day.
We're just out here in the bush looking for snails.
Want to join us?
Yeah.
Yeah.
Do snails live out here too?
You mostly see them in gardens.
Because they like our plants that we grow.
The snails you see in the garden are European garden snails.
They're very common in cities, but they're an introduced species.
That means people brought them here.
Once you get out of town, you'll start noticing our thousands of native Aussie snails.
They live everywhere from the dry deserts to the wet rainforests.
Wow.
Cool.
Do they all have a shell?
What about slugs?
They just have a slimy body.
Well, a slug is just a naked snail.
We wanted to know how snails get their shells.
Well, how about we use our imaginations to find out?
Yeah.
All right.
Let's shrink down to the size of an ant.
Yeah, that's about the size of a snail egg.
Alright, ready?
Here we go.
It's all dark.
And quiet.
Where are we?
On the ground, under a log in the top layer of dirt.
Dark hidden places like this are where snails lay their eggs.
There's an egg.
And there's another one.
One, two, three.
There are heaps.
Yes, snails lay up to 30 eggs at a time.
Hey look, that egg's hatching.
Oh, it's a teeny tiny snail.
Hey look, it already has a shell.
Yes, snails hatch out of an egg with a small shell and it will have this shell its whole life.
They have shells to protect their shell.
Is it part of their body?
Yes, it is.
It's attached to the snail.
They can't take it off.
How do they make it?
Snails have a very special body part called the mantle.
It's the organ that makes their shell.
The shell looks so thin, almost see-through.
It's not like those hard brown shells you normally see.
That's because the snail needs to eat something special for the shell to harden.
It's eating the egg.
It's a very important first meal.
It gives the baby snail calcium.
Calcium?
That's the stuff in cheese and yoghurt.
And our teeth.
And it's what the snail shells are made out of.
As the snail eats more calcium, the mantle keeps making more layers of soft shell and keeps pushing it out of the shell opening, and so it continues to spiral out bigger and bigger.
It sounds a bit like how our fingernails grow.
It happens so slowly we don't notice, but they're always growing.
Will a snail shell grow forever like our fingernails?
Yes, but it grows slower as they get older.
You can even see their baby shells.
If you look closely, it's that first swirl in the middle of the spiral.
And over the years, they keep adding more.
Hang on, but milk and cheese don't grow on trees.
No, they don't eat cheese and milk and yogurt.
No, there's calcium in lots of plants and even soil.
Why are they all sucking on that rock?
Some rocks have calcium in them, like that limestone.
Snails love limestone.
Native snails won't eat your garden, but they love to eat fungus and algae.
We often can't see it with our eyes because it's so small.
But rocks and trees can be covered in it and snails can smell it from a long way away.
They're eating a lot.
Munch, munch, munch.
Yeah, snails use their 20,000 teeth to get all the calcium meals they need.
20,000 teeth?
Will it bite me?
Don't worry.
It's vegetarian.
They're very, very small teeth.
Much too small to bite us.
Phew.
Hey, the snail went in its shell.
Is it scared?
No, it's inside its shell because it's daytime.
Snails are nocturnal.
It means you sleep in the morning and you wake up in the night.
Exactly.
If they get stuck in the sun, they could dry out and die.
And that's the biggest problem for snails.
The sun is more dangerous to them than any predator.
Like birds or lizards.
Try eating them.
And then it gets in its shell.
Yep.
Do you think it has a little house in there?
A TV.
And a sofa?
And a bedroom.
I don't think so because they can just hide up in their shells and that's why it's all empty.
Yeah, okay.
Maybe just a bathroom.
No.
Yeah, because they don't have a bum.
Let's take a look inside a grown-up snail shell.
There's not much to see in these tiny hatchlings.
Wow, the snail's body is a spiral too.
It fills up the whole shell.
All of the snail's body is inside the shell.
Yes, the shell protects all of the snail's important body parts.
The heart, the lungs, the kidneys and the stomach.
I didn't know there was so much to a snail.
So the part we see on the outside is just the head and its foot?
Yes, we call it a foot.
One big slimy foot.
Yeah.
What's that sound?
The snail keeps water inside its shell.
That way, if it's a hot, dry day, it can seal itself to a rock or a tree and stay nice and wet inside the shell.
Oh, so I shouldn't pick up a snail if it's stuck onto something?
No, it's trying to protect itself from the sun.
Some snails can even go to sleep for months at a time, so they can rest through the dry season and come out when there's enough rain.
This doesn't feel like water.
It's sticky and gooey.
It's slime.
They make two kinds of slime one for their bodies to stay wet and another slime to help the snail move around.
They have some slime under them so they can make the trails.
Whoa, look out!
Super slippery.
I reckon it's night time outside now.
Come on, we can see what the snails are getting up to now that it's dark.
Wow, there's lots of snails.
Come on, let's follow the slime.
Can we do snails too?
Yeah.
Let's get slimy.
Here I go.
Keep sliding.
Slime.
Slime flies when you're having fun.
So tight.
And we've made it... Five metres.
What?
That's like the length of a room.
That would take a snail half the night.
Snails prefer the slow lane.
How do they know where they're going?
They have little antennas and two eyes.
And they move their eyes around, I think, to look different directions.
Yes, but they don't see very well.
They see in black and white, and it's probably pretty blurry.
They've been getting around since before the dinosaurs, so they're pretty good at it.
Really?
Snails are older than dinosaurs?
By a couple of hundred million years.
Wow.
Wow.
They've been around for a long, long time.
How old are they?
If they stay out of the sun and get a lot of good food to eat, snails can live for five, even ten years.
That's older than me.
Come on, we have one more thing to show you.
Ah, we're at the beach.
There are so many beautiful shells in the sand.
Yes, and guess who made them?
Snails?
Of course, who else?
Because snails make shells.
All the shells you find at the beach that have those lovely spirals come from sea snails.
There are thousands of types of land snails and even more that live in the sea.
I had no idea that sea snails made the shells.
So what else makes shells?
Like this flat one.
Clams, oysters, mussels, they're relatives in the mollusk family.
Oysters and clams are related to snails?
Yep, and they all grow their shells from a mantle in a similar way.
Even the really, really big ones?
Like this conch?
Home to a really, really big snail.
I'm never going to look at a shell the same way again.
Snailed it.
So George, a snail makes its shell when it's growing inside the egg.
Once a baby snail.
And it will keep it for the rest of its life.
For five or ten years.
Inside a snail's body is an organ called the mantle.
The mantle makes the shell.
When the snail hatches out of its egg, the shell is thin and soft.
But then it eats its egg for the calcium.
And these soft layers then harden into a tough shell.
The snail will look for more calcium-rich foods for the rest of its life.
From plants and dirt.
A rocks eel.
To keep laying down more layers of shell that grow bigger and spiral outwards into that famous snail shack.
So swirly.
There are thousands of types of snails on land and even more under the sea.
So next time you're in the bush or at the beach and you spot a beautiful spiral shell, you'll know that once upon a time, a little snail spent years making every single swirl.
Imagine This is an ABC Kids Listen podcast, hosted by me, Dr Neeraj Lal.
A big thanks to our guests, the Snail Whisperers, Drs John and Laurel Stanisic, and to all the kids who helped make the show.
Today's episode was written and produced by Samia Bella, with sound design by Wei Nguyen, and was made on Wurundjeri Woiwurrung Turbul, Darug and Gadigal lands.
Our executive producer is Emma Gibbs.
For more podcasts to play, music to move and stories and soundtracks for sleep.
Download the ABC Kids Listen app free from your app store or look for ABC Kids Listen on the ABC Listen app.
