A Tiny Darwin's Bark Spider Shoots a Silk Line Over 25 Meters to Begin Spinning Her Giant Web

SOLVED: The silk of Darwin's bark spider (Caerostris darwini), named after the naturalist, Charles Darwin, is the strongest biological material ever discovered (see the photo). In fact, many of the mechanical properties of the silk supersede those of steel. While the Young’s modulus for steel ( 2.00 × 1011 N/m2) is larger than the silk (1.15 × 1010 N/m2), the density of the silk is much less, such that the strength-to-density ratio of the silk is about five times that of steel. Consider a 10.0-c