The tensile strength of dragline spider silk is almost equal to high-grade steel. In terms of toughness, it is comparable to synthetic fibers like nylon. That's why spider silk finds so many uses, from fishing webs and textiles to optic fibers and crosshairs for rifle scopes.
Both spider webs and cobwebs are made by the air-breathing creatures we call spiders. The only difference is that cobwebs (primarily irregular in form) are mostly made by two spider families called Theridiidae and Linyphiidae. What we usually call "spider webs" are the neat, orderly ones built by families like Araneidae, Nephilidae, Tetragnathidae, and others.
Here's a look at the difference between cobwebs and spider webs, the protein fiber structures that serve as nests, means of transport, and prey traps for these arthropods.
Cobweb vs. Spider Web at a Glance
The quickest way to tell them apart is to look at the shape. A cobweb is a random, three-dimensional tangle. A classic spider web is a flat, orderly wheel. Here's the side-by-side.
| Feature | 🕸️ Cobweb | 🎯 Spider Web (orb) |
|---|---|---|
| Shape | Irregular, tangled, three-dimensional, no clear pattern. | Elegant and orderly, a flat wheel of spokes and spirals. |
| Made by | Mainly the Theridiidae (comb-footed spiders) and Linyphiidae (money spiders); also long-legged Pholcidae. | Orb-weavers, Araneidae, Nephilidae, and Tetragnathidae, among others. |
| Made of | The same thing, spider silk, spun from glands called spinnerets at the tip of the spider's abdomen. | |
| Where you see it | Corners of rooms, ceilings, and sheds, often dusty and abandoned. | Gardens, gates, and bushes, strung out in the open to catch flying insects. |
| Main job | A nest and a sticky trap that works well in tight, sheltered spots. | A precise flying-insect trap built out in the open. |
A tangled, dust-catching mesh with no pattern, built by comb-footed and money spiders in sheltered corners.
A neat orb of spokes and spirals, woven by orb-weavers out in the open to snare flying insects.
All About Cobwebs
The Family
The irregular, tangled webs created by our eight-legged friends are commonly known as cobwebs. The origin of the word cobweb may be attributed to an old English word for spider, which is coppe. Cobwebs are made by the family known as the Theridiidae (also called tangled web spiders, cobweb spiders, or comb-footed spiders) and the Linyphiidae, also called the sheet weavers or money spiders.
The Architecture
The Theridiidae are one of the largest spider families, with more than 2,200 species spread over 100 genera. They show great variety in the webs they build. Mostly they make three-dimensional, gum-footed tangled webs. These have frame lines that anchor the web to its surroundings and outer lines made of sticky viscid silk. Each species builds its web a little differently. A sister family, Nesticidae, also builds gum-footed tangled webs with no clear orb-like pattern.
Linyphiidae Family
The Linyphiidae are tiny spiders. They prefer to build sheet webs, dense, flat structures that act as nests and good traps for catching prey. Members of the long-legged Pholcidae family also create irregular cobwebs. Tangled webs can be very good at catching prey in tight, sheltered spots. Perhaps that's why they've been preferred over the course of evolution.
So these are the families you can mainly blame for the cobwebs in the corners of your house. There may or may not be a spider nearby to claim ownership of these webs. Spiders keep moving on as they follow the availability of prey. The abandoned webs eventually gather dust, making them more visible. Many times, cobweb strands are not even part of a web at all, they're just traveling spider silk, ropes that a spider launches to move around.
Frequently Asked Questions
What is the difference between a cobweb and a spider web?
Both are made of spider silk, but cobwebs are the messy, tangled, irregular webs made mostly by the Theridiidae and Linyphiidae families, while 'spider webs' usually means the neat, patterned orb webs built by families like Araneidae, Nephilidae, and Tetragnathidae. The main difference is architecture.
Are cobwebs and spider webs made of the same material?
Yes. Both are spun from spider silk, a protein made in special glands called spinnerets located at the tip of a spider's abdomen.
Why do cobwebs in the house gather dust?
Spiders often move on to find more prey and abandon their webs. The abandoned, sticky strands then collect dust, which makes them more visible in the corners of a room.
Where does the word 'cobweb' come from?
It may come from 'coppe', an old English word for spider. So a cobweb is literally a 'coppe-web', a spider's web.
How strong is spider silk?
Very strong. The tensile strength of dragline silk is almost equal to high-grade steel, and the silk of Darwin's bark spider is about ten times tougher than Kevlar.
Cobweb or Spider Web? Take the Quiz!
5 quick questions. Can you tell the tangle from the orb, and name the silk?
All About Spider-webs
What's a Spider-Web
The elegant and sophisticated webs designed by spiders are generically known as spider webs. These are created by orb-web-producing families like Araneidae, Nephilidae, and Tetragnathidae, among others. Spider webs (just like cobwebs) are created from a proteinaceous fluid emitted by specialized glands called spinnerets located at the abdominal tips of spiders. The material they are made of is known as spider silk.
Specialized Glands
There are seven types of specialized glands that create seven different types of spider silk. Each type is used for a specific part of a web, or for a special purpose besides web building. The two most important types are viscid silk (wet, elastic, and sticky, used to form the outer spirals of a web and catch prey) and dragline silk, which is tough and dry and forms the radiating arms that give the web its strength.
Types of Webs
Depending on the species, spiders are known to have one, three or four types of glands. The spider's web can be broadly grouped into four types, other than the common cobwebs and sheet webs:
- Orb-webs: mostly created by the Araneidae, Tetragnathidae, and Uloboridae families of spiders
- Funnel Webs: spun by spiders belonging to the Hexathelidae family
- Tubular Webs: built by spiders like Segestria florentina
- Tent Webs: built by spiders belonging to the genus Cyrtophora
Different Uses of Spider Silk
There are different types of spider silk, and each serves a different purpose:
- Building the main framework (drag lines) of a web to catch prey
- Building the spokes of the web
- Wrapping and packing freshly caught prey for later consumption
- Protecting an offspring
- Ballooning out with a drift
- Serving as a source of food
- Acting as guidelines
- Serving as pheromonal trails
- Acting as an alarm line
- Nest building
To conclude, the difference between orb-like spider webs and cobwebs is primarily architectural, owing to the different spider species that they originate from.
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Fun fact for today!A cobweb and a spider web are both made of silk, the big difference is the shape each spider weaves!