When a spider wants to make a web, it squeezes the silk out of the two small holes at the back of its body called spinnerets. The moment it hits the air, the silk dries into a line that looks like a long strand of hair. Many spiders use their sticky silk webs to catch food, which consists of tiny animals. Some spiders use silk as draglines, which are long lines of silk the spider hangs onto as the wind blows it through the air. Some spiders spin silk webs, and others line their burrows with silk.
Many spiders lay their eggs in silken sacs.
All young spiders, and some adult males, release long silken threads to float or ride the wind to new areas. This is called ballooning. Although spiders can live almost anywhere in the world, some like it where it is very humid, and some like it where it is very dry. Some spiders live underground and catch their prey by jumping out at them. Others live in trees and capture their prey in their webs.