Horseshoe crabs.

Now they are a very, very ancient body design on DDE.

What I wanna know is just how old man with the answers is Dr Ward.

Well, well, the first fossil records of horseshoe crabs like this are from the mid salary in about 450 million years.

Yeah, that's right.

He did just say 450 million years.

So have they changed much in that time?

Well, yes, there trains tremendously.

However, their external body features have not or quite recognisable today.

This is a fossilized, of course.

You crap.

Yes.

This is actually from the meds or the time of the dinosaurs.

Looking at this, it looks almost identical to the to the external aspect of the modern horseshoe crab.

The horseshoe crab is unquestionably one of nature's great survivors, and it's 450 million years of existence is withstood.

Several major extinction events have worked out great swathes of life.

Why did these managed to survive those five great extinction phases to g o?

You put your finger on one of the great side of the questions of all time.

Why did that happen?

Why does some of these creatures go extinct?

Another one survive and I don't have an easy answer.

But there are many hypotheses that have been suggested.

Certainly something major happened of the Earth.

So I want to meet this weird survivor to find out just how it's withstood.

Maybe half a 1,000,000,000 years, whether today it really is reaching the end of the line.

But I'm not going to the ends of the Earth, in fact, but I got to do is get out of New York City, but not far outside the city limits.

It feels like stepping back in time.

The horseshoe crab spends most of its life scuffling around in the mud at the bottom of the ocean.

So how am I gonna get my hands on one?

Well, in Delaware Bay, a quirk of evolutionary history meets a quirk of coastal geography.

Horseshoe crabs come ashore to spawn, and the largest number of them congregate.

Right here.

You'll see my Harry Kagle.

So the shoreline is the place to start looking.

I know it's a very local before it's covered in this sort of Hey, is now.

This is something I've been doing against.

It sells a nipper.

That's one of the one of the conchs, one of the conscious.

What's great about it is the rules of the same wherever you are in the world that we just happened to be in North America, and that's the Atlantic.

But the stuff that comes out is what we're interested in.

That's a mermaid's purse.

That's what we used to call them as kids.

On that left.

Is the egg case off a skate from a national point of view, if you scour this, you could learn an awful lot about what's going on out there.

And it seems I'm on the right track because there's plenty of evidence of ex horseshoe crabs.

If your crab broken.

If you lost the part, you better find one here.

I mean, you've got loads of it so that we got we got the the office over there of one.

Crab is like a wrecking yard for these animals.

There's bits of crab strewn as far as the eye can see, And it's just sad knowing that that there is the end, I guess 20 years of life over here now, this isn't just a crab graveyard.

They're they're everywhere they're signs of life here too.

You think our poor little thing that they are, they even got to adult hood.

Mister, Come.

But this is the Mt.

Skin off a horseshoe crab hopefully is still out there alive right now, growing up very mind here that horseshoe crabs aren't crabs a tool.

There are totally unrelated group of marine arthropods.

The Allied Thio gets the spiders and scorpions, all of the insects.

They all have their skeletons on the outside and XO skeleton made of a substance known as chitin.

Now you need to grow.

And if your skeletons on the outside that poses a bit of a problem.

So what they do is underneath their skin, they develop another skin on.

At some point, they crawl out there, splits their skin, their crawl out of it, expand a bit their skin or their new skin or harden informed brand new skeleton.

And this here is the old skin that has been left behind.

I've always been fascinated by this process because the details off the animal laurel there it's just a ghost of its former self.

So I could Krusty Cuteness ghost.

They have been crabs here, but if they only come ashore to spawn Hammer Gonna find a live one.

Like most living things, horseshoe crabs have a body clock, but theirs is incredibly well tuned to the rhythms of the sun, the moon and the tides.

They maximize their chances of meeting a mating by coming together on these Bt's on the highest of the spring tights.

Now these crabs might be underwater Rolexes.

But my timekeeping has never bean great with moons and tides and time differences that juggle.

The question is, Have I got my timing's right to be here When the invasion lands these animals, they perform one of the greatest natural spectacles for me anyway in the world.

How did they get their timing so precise?

That is that it's a good question.

There are a number of number.

It's interaction, the number of factors, the idea.

Because, as you mentioned, it's almost time of the kind of the shelf in the year.

And then they want to come up and congregate to mate.

There's no they're not congregating.

Normally eso In the high tides of spring and early summer, you get immense notes where an entire beach will be just covered with pears.

And the idea is that there's some photo period as the days get longer and it gets warmer that there's a many creatures since spring coming that way.

Many arthropods, in fact, they have very, very accurate photo sensors.

So it's really a combination of temperature photo period to get this immense number out there one time.

So it's back to Delaware Bay and turn to follow a bit of local knowledge on the evening of the spring.

New mood.

I've come to Pickering Beach with resin Ecologist Glenn Governor is my favorite beach for this because it never fails to impress.

As the tide peaks, it seems that we and the crabs have synchronized our lives perfectly, and we just stumbled upon a breathtaking invasion, one of nature's greatest and weirdest events.

Oh, good.

Look, Look, At least this is the heli sporting ritual of hundreds of thousands off weird creatures on the seas, bristling with if you look, it looks just like a lot of pebbles, but they're not every single one of these is it as far as the eye can see, and beyond the tide line is a crawling carpet of crabs.

Visitors from another time.

So really, just in the fringe off a big event that's occurring right here.

This is just their turn.

Just an orgy.

I mean, I'm not used to this.

Normally, this program involves me looking for something that's not a chance of sick, lumbering about for a whole hour, trying to find it as a show on, then usually failing or getting distant glimpse of it.