Mechanical Properties and Factors of Safety of Spider Drag-Lines

Abstract

Experiments were carried out to determine the strain energy capacity and breaking strain of spider drag-line silk. These properties are discussed in terms of a mathematical model of a spider falling on a drag-line. It was found that the strain energy capacity of the drag-line was insufficient to absorb the potential energy lost by a falling spider and that in order to avoid failure of the drag-line the spider dissipates energy by other means, particularly by using its inertia to draw drag-line silk from its spinnerets.