These graphs represent transects collecting the thickness (μm) of stress lines moving from the pulp cavity (to left) to the outer edge of the tusks (to right). Green boxes highlight durations without visible stress lines and gray boxes highlight portions of the tusk with closely spaced stress lines suggesting a stressful interval. The height of the boxes represents the thickest stress line during such period. See Supplementary Fig. 1 for transects from entire sample.