There are spiders all around the world. Scientists think there are about
40,000 spider species on Earth. Many people find these small creatures very scary,
and want to stay away from them, but others find the webs they make beautiful.
Webs are made from silky threads,these threads of the spider silk are 30 times thinner than human hair.
If a single thread of this silk went all way around the Earth it would weigh less than half a kilogram.
It's the strongest kind of thread in nature, but it is amazingly light and very flexible.
This is an orb weaving spider. And this is a bat. The bat uses its hearing to help it to fly at night without hitting anything.
Well . . . almost anything. This spider's web is huge and very sticky. Suddenly, the bat is trapped. And that is that.
The net casting spider uses a different kind of web. It doesn't make a web. Instead, it and its sticky silk hang from above, like a trap.
Then it waits for it meal to walk by. Suddenly, the spider jumps and throws its silk out to catch the insect.
Then, it folds the silk around the insect, so it can eat it later.
Different spiders make different kinds of silk. Each type of silk has a different use.
Sometimes their web are in the shape of long threads. These threads are very sticky liquid all over them.
When an insect touches the thread, the liquid covers it, and it stops the insect from getting away.
A spider knows exactly what is happening at the center of its web. It keeps on foot on a thread that goes all the way to the center.
When an insect moves on the web, the spider can sense the movements. It realizes its dinner has arrived. When the spider isn't hungry,
it keeps the insect in silk, to eat later.
It is combination of strength and flexibility in a spider's silk that has provided it with its next meal.