A silk cocoon is a natural polymer composite. Silkworms devote a considerable proportion of their mass and energy gained from the larva stage to the production of silk for constructing cocoons, and then spend most of their life in them as pupae before emerging as moths. The wild cocoon is suggested to provide protection for the pupae against the environment, parasitism and predators, while Bombyx mori cocoon is a human cultivated species providing silk fibres for textile industries for more than 4000 years.