Protein fibers are natural fibers made primarily from proteins, which are essential building blocks of life. Common examples include silk, derived from the cocoons of silkworms, and wool, sourced from the fleece of sheep. These fibers are known for their strength, elasticity, and ability to retain warmth, making them popular choices in textiles. In addition to their practical uses in clothing and upholstery, protein fibers also have unique properties. For instance, silk has a smooth texture and a natural sheen, while wool is excellent for insulation and moisture-wicking. Both types of fibers are biodegradable, contributing to sustainable practices in the fashion industry.