MA silk is well known for its outstanding mechanical properties. It has been inten­siveЧly studied by a large number of laboratories across the globe. The majority of these studies have focused on the stress-strain behavior of MA fibers because these values can be normalized to the dimensions of the tested fiber, which allows for comparison across different lengths and thicknesses of materials. Relative to high tensile steel, the breaking stress for dragline silk is comparable but it is considerably more extensible, leading to material that is 30 times tougher than steel.23 Dragline silk also outperforms Kevlar, a synthetic fiber used for ballistic armor, and is 3 times tougher. Analysis of the literature reveals much variability in the published mechan­ical properties for MA silk. In part, some of the differences can be attributed to the fact that different spider species have been used to collect MA fibers for the tests.24 However, it must be emphasized that the methodology for fiber collection can have a significant impact on the mechanical properties.25 In particular, it has been clearly demonstrated that altering the reeling speed or force during the fiber collection can influence the mechanical data.26 Humidity, the age of the spider, ultraviolet light, and the duration of storage of the fibers before analysis have also been reported to have an impact on the mechanical properties of the materials.27