Mulberry Silk comes from the silk worm. The breeding of the silk worm in order to produce raw silk is called sericulture. The larvae of the silk worms have a preference for white mulberry leaves, hence their name. They spin their cocoon around them to protect them during their metamorphosis into a moth. The cocoon is made up of a single thread of raw silk around 900 m long. Several strands of silk are used to create a thread.