How do we know?
↻ One of the pages with a moving picture
Scientists tested the silk of Darwin’s bark spider in a lab.
- Spider silk is made of protein. It comes out of body parts called spinnerets.
- First the spider lets out a bridge line. It drifts on the breeze until it snags on something.
- Next come the straight spokes, like on a bike wheel. Spoke silk is not sticky.
- Last, the spider lays a sticky spiral. That’s the part that catches insects.
Scientists pulled silk from Darwin’s bark spiders and tested it in a lab. It was more than twice as tough as any silk measured before, and over 10 times tougher than Kevlar.
Darwin’s bark spider lives in Madagascar. It builds webs across rivers, with anchor lines up to 25 meters long. A round web like this is an orb web.
Some spiders have up to 7 different kinds of silk glands. Each one makes silk or glue that does a different job.
Wow number
7 Some spiders have up to 7 different kinds of silk glands. Each one makes silk or glue that does a different job!
Myth or fact?
All spiders build webs. Myth. Not all spiders build webs, but they all use silk somehow.
Some threads in an orb web are not sticky. Fact. The spokes are dry silk. Only the spiral is sticky.
Think about it
Why do you think the spokes are not sticky?
Where in the world?
Madagascar where Darwin’s bark spider builds webs across rivers, with anchor lines up to 25 meters long — 18.7669° S, 46.8691° E.
Where these facts come from
Every number on page 67, and who measured it
This page tells us what spider silk is made of and how the web's spokes work.
Fall is spider season as orb-weavers spin bigger webs — University of Illinois Extension
extension.illinois.edu/blogs/naturalist-news/2021-09-16-fall-spider-season-orb-weavers-spin-bigger-webs
We checked it on 31 October 2026
This page tells us the steps a spider follows to build an orb web.
Orb Web Construction — The British Arachnological Society, a group of spider experts
britishspiders.org.uk/orb-webs
We checked it on 31 October 2026
This page tells us about the different silk glands, and that not all spiders build webs.
Weave a Web — A spider science lab at the University of Nebraska
hebetslab.unl.edu/portfolio-posts/weave-a-web
We checked it on 31 October 2026
This page is the science paper about Darwin's bark spider and its super-tough silk.
Bioprospecting Finds the Toughest Biological Material: Extraordinary Silk from a Giant Riverine Orb Spider — PLOS One, a science journal
journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0011234
We checked it on 31 October 2026
Has this changed?
How spiders spin webs is not going to change.
Scientists keep finding new silks. Darwin’s bark spider’s silk beat the toughness record that had been set before.
Words from this page
- protein
- A building material that living things make. Silk and hair are made of protein.
- spinneret
- A body part of a spider that silk comes out of.
- orb web
- A round web with spokes and a spiral.
Try it!
Build a web with yarn and tape.
1. Ask a grown-up for some pre-cut pieces of yarn and some tape. 2. Tape yarn spokes across the legs of an upside-down chair, all crossing in the middle. 3. Add a spiral of tape, sticky side out. Toss paper-ball “bugs” at it.
What happens: the paper bugs stick to the tape spiral but not the yarn spokes, just like a real orb web.
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