Silk is produced using 6 finger-like glands or spinnerets. Not all spiders spin webs. Most spiders lay eggs within silken sacs attaching them to webs, twigs or leaves. Some spiders carry these sacs until the eggs hatch. Spiderlings resemble adults and are often cannibalistic.
All spiders are predators, feeding mostly on insects.
A few large species do prey on vertebrate animals. Spiders are considered helpful because they keep the insect population down.