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  • [MUSIC]

  • Think about this: Wherever you're sitting right now, chances are there's a spider nearby.

  • Which means there's also a spider web.

  • And you should be excited about that, because spider silk is awesome.

  • Spiders manufacture something stronger, stretchier, or stickier than just about anything humans have engineered.

  • A thread of spider silk is nearly invisible, which is why you've probably walked through it with your face.

  • Yet when it comes to strength, some spider silk fibers rival steel and Kevlar.

  • Imagine this: A silk cord about the diameter of a garden hose could hold up a passenger jet.

  • So how does such a tiny animal weave such an amazing material using nothing but its rear end?

  • I wanted to find out, so I went to the American Museum of Natural History to meet Dr. Cheryl Hayashi,

  • who's maybe the world's #1 expert in the science of spider silk.

  • Everybody knows that spiders make silk, but I don't think most people realize just how

  • many kinds of silk spiders make.

  • There's over 46,000 described species of spidersand most spiders make four, five,

  • six, seven, eight kinds of silk.

  • So if you do the math, it's huge!

  • So this is Nephila clavipes, the golden orb-weaver, and she can make seven different types of silk.

  • Seven different kinds of spider silk?

  • In that tiny little body?

  • Yeah!

  • Well, some people don't think it's a tiny little body

  • It's not the smallest spider I've ever seen!

  • When you look at the golden orb weaver's trademark web, you're actually looking at

  • several different types of silk.

  • There's the dragline silk: The spider drags it behind like a climber's safety rope.

  • It also makes up the web's outer frame.

  • There's one silk to guide the web's construction.

  • The spiral that traps prey, is actually a mix of two more silks: A stretchy silk covered

  • in a sticky glue-like silk on top.

  • There's a cement-like silk to attach the web to whatever it's hanging on.

  • There's a silk for wrapping up prey.

  • They even wrap their eggs in silk.

  • Seven different silks, all made by one spider.

  • So what exactly is this stuff?

  • Spider silk is made of proteins, and the dominant proteins inside a silk fiber are these specialized

  • category of proteins called spidroins, which stands for spider fibroins, that are unique to spiders.

  • Inside the body, all of the silk glands have liquid protein in them.

  • So it's liquid protein, and when I dissect a spider and I take out a silk gland, and

  • I break the gland open, it has the consistency of honey!

  • It's a viscous, gooey substance that's in there.

  • And it's highly-concentrated silk protein.

  • It kind of makes you wonder what an anatomically correct Spider-Man would look like.

  • The raw ingredients for every protein chain are twenty amino acids, and the recipes for

  • these chains are coded in genes.

  • The order of amino acids in these chains determine what a protein looks like, and what it will do.

  • And spider silk proteins are built in a very special way.

  • Imagine a silk molecule like a long train, made up of different boxcars.

  • Inside each type of boxcar is a string of amino acids.

  • In any one type of silk, we see the same boxcars over and over all the way along the train.

  • This unique pattern is what makes each silk so specialized.

  • Spiders have cooked up some equally specialized ways to use these silks.

  • Like the trapdoor spider, which weaves a camouflaged shelter from silk.

  • The ogre spider, that it casts out a silk net like a fisherman.

  • Or the redback spider, who weaves a trap in the form of sticky spring-loaded snares.

  • Other spiders shoot venom-laced deadly silly string silk.

  • Small spiders can even ride the winds on silk sails, a trick calledballooningthat

  • can carry them kilometers into the sky.

  • To find the origins of spider silk, we have to go a long way back.

  • This is fossil amber, it's from a Burmese deposit, and there's a spider in here, and

  • this is 100 million years old.

  • Do you want to touch a 100-million-year-old spider?

  • I need to be very careful.

  • I'm holding a piece of the world from 100 million years ago, and there's a spider

  • in there that was already making silk like spiders do today?

  • Yes.

  • 100 million years old!

  • I can keep this, right?

  • -Sorry about that! -It'll be our secret.

  • Here's another fossil spider, this one's not quite as old: only 20 million years old.

  • Only 20-million-years-old?

  • Practically yesterday!

  • This one is just beautiful.

  • I mean, you can see the spider inside.

  • It's posing like a spider!

  • It knew that we would find it one day, and it was like, “I'm gonna give them a really good pose.

  • I'm going to do my best spidering.”

  • Thank you, I really appreciate it!

  • But Dr. Hayashi doesn't just study how spiders evolved and how they make silk.

  • She also studies its mechanical properties.

  • If you're picturing her pulling on spider silk with tiny tweezers, you're not far off.

  • This is one strand of dragline silk, that what's on this card.

  • She unweaves these single silk strands by hand, and mounts them into a special machine

  • to test how much pulling it can take before it breaks.

  • And you can see there's a fiber connecting that.

  • So the only thing connecting this part of the machine: this clamp to this clamp, is the silk fiber.

  • Can we pull on it?

  • We can pull on it!

  • We're going to break this spider silk so good.

  • [SUSPENSEFUL MUSIC]

  • Weight for weight, almost nothing we humans have invented is as strong, as stretchy, or

  • absorbs energy as well as some spider silks.

  • So naturally, we're trying to figure out how to manufacture and weave this stuff for ourselves.

  • The approach is you take the spider silk gene, and you move that silk gene into another organism

  • such as bacteria, a plant, a silk worm, or even goats.

  • Goatslike?

  • Where is it coming out of the goats?

  • So in the goat, it actually comes out, it's expressed in the mammary gland.

  • So it comes out with the milk.

  • What happens if you drink that milk?

  • Do you get special powers?

  • Um, I haven't tried that myself.

  • I'm going to market spider silk milk goat cheese.

  • You heard it first!

  • Spider goat silk is still experimental, but it shows us something really amazing about the power of evolution.

  • With all our tools, and all of our knowledge we haven't invented a material as awesome as spider silk.

  • We're still no match for millions of years worth of nature's experiments.

  • Well, I made a new friend.

  • I made two new friends.

  • [SPIDER NOISES]

  • She's like, waving to the camera.

  • You know, that's what they say about spiders, you put a camera on them.

  • I know!

  • Hamming it up!

  • Hamming it up.

  • She's saying "Hi Mom!"

[MUSIC]

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