Darwin’s Bark Spider Spins Ultra-Tough Silk and Bridges Rivers Across Madagascar

A Madagascan spider, Darwin’s bark spider (Caerostris darwini), weaves dragline silk that is the toughest biological material measured to date, absorbing more energy than Kevlar by roughly tenfold; its webs span rivers with bridge lines up to 25 meters. The toughness arises from a mix of solid strength and unusually high elasticity, and researchers note the silk isn’t yet mass-producible due to the impossibility of farming spiders. The work also highlights bioprospecting as a targeted approach to discovering extraordinary natural materials.