Why do spiders make silk?

Caterpillars << please note the spelling, it will help you find more information!

They make silk to spin a cocoon. The caterpillar eats a lot of mulberry leaves and its body transforms the leaves into whatever nutrition it uses to make silk. (Kind of like a spider makes thread inside itself.)

The caterpillar makes a cocoon around itself to protect itself while it becomes a butterfly.

But, the ancient Asian people somehow figured out that you could take these cocoons and cook them, which loosens the silk so that a person can "unwind" the cocoon -- basically, a person can un-spin the cocoon that the caterpillar was spinning.

Of course the caterpillar dies from this.

You can also look up "silkworm" on Wikipedia.

Hope that helps! HC