Modern ungulate long limb bone shaft fragment that was experimentally trampled, showing damage typical of that action, including small fracture edge notches and micronotches and conchoidal flaking of its cortical surface (red arrows) and linear trampling marks (white arrow) (A). Marks H1 and H2 on the fossil DIK-55–3, which show, respectively, small notching and conchoidal flaking (H1) and a winding trajectory (H2) (B) that are similar to the modern bone surface trampling damage illustrated in A, C, and D. The winding shallow groove of mark H2 emanates from the fossil's breakage plane, as is common in trampled bones, including that illustrated in C. Note also the shallowness, winding trajectory, and internal microstriations of the experimentally produced trampling mark in D. The image in A is courtesy of R. Blasco and J. Rosell. The image in B is modified from McPherron et al. (1). (Scale bars: 1 mm in C and D.)