The silken thread of the spider is the most resistant natural fibre that is known to man.  It is produced by a special gland found in the abdomen of the spider.  On contact with air, the fibre hardens immediately.  Many spiders use this thread to weave a cobweb and then utilize the latter as a trap.  Insects which get caught in the web are stuck and represent an easy prey for the spider.  Some spiders employ the silken threads to protect their eggs or build a safe space.