Did you know that spiders eat their own webs? It sounds strange, but it’s actually a brilliant survival strategy. Webs allow a spider to catch prey without expending energy by running it down, making them one of nature’s most efficient food-gathering tools. The hair and claws on spiders’ legs let them cling effortlessly to their webs, while the oils on their bodies keep them from sticking. But producing all that silk is costly — so rather than let it go to waste, many spiders simply consume their old or damaged webs to recycle the proteins, which get reused to spin fresh silk. It’s essentially internal recycling, and some spiders that rebuild daily eat their old webs every single day.
So how does silk actually work?
Spiders produce silk from glands at the tip of their abdomen. Inside their bodies, it’s stored as a highly concentrated liquid protein — but the moment it leaves the body, it transforms into solid thread. A single spider can produce up to seven different types of silk, each with its own job. One type makes the web stretchy enough to absorb the impact of an insect hitting it at full speed. Another makes the thread less brittle. Still others protect the web from bacteria and fungi and keep it moist.
Webs aren’t just for catching bugs
Not all spiders catch prey in webs, and some don’t build webs at all. Hunting spiders trail silk drag lines behind them as safety nets while they stalk. Others spin specialized silk to create egg sacs or small protective shelters. Perhaps most surprisingly, some spiders use silk to catch air currents and essentially go sailing — sometimes migrating hundreds of miles through the sky. These mass ballooning events can involve millions of tiny spiders at once. When they land — or get blown off course by unfavorable winds — their silk can blanket the ground in thick white layers, as happened near Memphis at the end of 2015.
Meet the record breakers
Darwin’s bark spider, discovered in Madagascar in 2009, produces the largest known orb webs — up to 30 sq ft — and builds enormous bridge-like webs spanning rivers and lakes up to 82 ft wide. By stringing silk across open water, it captures fast-moving prey like dragonflies that swoop along the surface. The female spends days alone building and reinforcing those bridge lines.
On the other end of the spectrum, the diving bell spider of Europe and Asia has figured out how to live entirely underwater — the only spider known to do so. It constructs a bell-shaped web anchored to aquatic plants and inflates it with air carried down from the surface, creating a bubble it calls home.
Wait — what even is a cobweb?
Here’s a fun bonus fact: not every spider web is a cobweb. Technically, a cobweb is an abandoned spider web — one that’s collected dust and debris and become tangled and messy over time. Biologists also use the term to describe a specific type of spider that naturally builds irregular, tangled webs rather than neat orb shapes. So that creepy dusty web in the corner of your ceiling? That’s a cobweb. The fresh one glistening outside your window this morning? Just a web.
Stronger than steel
Spider silk is pound-for-pound roughly five times stronger than steel and comparable in tensile strength to Kevlar. Scientists are actively studying it in hopes of creating a super-tough synthetic material with similar properties. Nature has been engineering this stuff for hundreds of millions of years — and we’re still trying to figure out how to replicate it.