Why do spiders spin silk that is stronger than steel by weight?

Spider silk is produced from specialized glands and spun through spinnerets into fibers with remarkable mechanical properties. In many species, the silk combines high tensile strength with elasticity, allowing webs and draglines to absorb shocks from struggling prey. Scientists have long studied silk because it can outperform many man-made materials in strength-to-weight terms. Different silk types serve different functions, from sticky capture spirals to rigid frame lines and egg-case material. The first detailed modern descriptions of silk’s structure came from biochemical research in the 20th century, and synthetic spider-silk research remains an active field.