How Do Spiders Make Webs?

Spiders make webs by spinning liquid silk from organs called spinnerets near the back of their bodies. Ounce for ounce that silk is stronger than steel and tougher than Kevlar, and a single spider can produce up to seven different types of it for different jobs. An orb weaver can build an entire web from scratch in about 30 to 60 minutes.

Silk starts as a liquid

Inside the spider, silk is a gooey protein liquid stored in special glands. It only turns into solid thread the moment it is pulled out of the body.

The spinnerets act like tiny, controllable nozzles. As the spider draws the liquid out and stretches it, the loose proteins lock together and harden into a strong, finished fiber.

That stretching is the secret step. It is not heat or any chemical that solidifies the silk, it is the physical pulling, which aligns the proteins into a fiber that is astonishingly strong, stronger than a steel strand of the very same thickness.

Not all silk is the same

A web is not made from a single material. A spider can produce up to seven distinct kinds of silk, and each one is tuned for a specific task in or around the web.

• Dragline silk — the strong, stiff stuff used for the web's frame and the safety line the spider dangles from.
• Sticky capture silk — coated in tiny glue droplets to trap insects that fly straight into the web.
• Wrapping silk — soft, flexible thread used for bundling up caught prey to eat later.
• Egg-sac silk — tough, protective fiber spun specifically for wrapping and shielding eggs.
• Each type comes from a different gland, and the spider switches between them on the fly as it works.

Building an orb web step by step

An orb weaver works fast and follows a clear, repeatable plan. First it releases a single line that floats on the breeze until it snags something across a gap, forming a bridge.

From that bridge it lays down the outer frame, then runs non-sticky spokes radiating out from the center like the spokes of a bicycle wheel.

Finally it spirals inward, laying down the sticky capture thread that actually catches prey. The whole build takes roughly 30 to 60 minutes, and many spiders eat the old web for protein and rebuild a fresh one every single day.

How spiders avoid their own trap

If the web is sticky enough to catch a fly, why does the spider not get hopelessly stuck in it too? The answer comes down to very careful footwork.

Only the spiral capture threads are coated in glue. The radiating spokes that the spider actually walks on are the dry, non-sticky kind, so it travels around the web along safe, glue-free lanes.

On top of that, spiders have slightly oily legs and tiny gripping claws, which let them touch even the sticky thread when they need to without snagging on it.

Why steel would lose

Saying spider silk is stronger than steel sounds like marketing hype, but by weight it genuinely holds up. Silk can also stretch and absorb a sudden impact without snapping, which is exactly where it leaves stiff materials behind.

That rare combination of strength and stretch is why engineers keep trying to copy it for everything from body armor to dissolving medical sutures, and mostly keep failing to match what the spider does for free.

Scientists have even spliced spider-silk genes into goats so the protein turns up in their milk, all in an effort to mass-produce the stuff. After decades of trying, the humble garden spider still does the job better than any lab on Earth.

A spider builds a structure stronger than steel by weight, from scratch, in under an hour, every single day.

Try It Yourself

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Keep reading: how many species are on Earth and how bees make honey. Both go deeper on the same rabbit hole.