<p>Surprisingly, the pelvis of Neandertal males shares more features with the human female pelvis than with the human male pelvis. Many of the differences between the Neandertal male pelvis and that of the <i>Homo sapiens</i> male seem to stem from the unusual anterior position of the acetabula (hip joints) in <i>H. sapiens</i> males and the subsequent increase in the horizontal anteroposterior distance between the joint and the line of gravity. We suggest that the forward migration of the hip joints transforms the modern human male pelvis into a shock-absorbing device that cushions the drop of the center of mass with every step and at the same time stores potential energy in the flexor muscles of the thigh, causing the pelvis to bounce back. The thickening of the ramus and the ensuing modifications are a response to the increased adductor force required on the pubic side to counterbalance the larger moment generated by the longer body-weight lever arm on the opposite side of the hip joint fulcrum. The shock-absorbing device seems to benefit modern males, mainly in long-distance walking. Obstetric demands apparently prohibit the modern female pelvis from adopting this specialized device. The <i>H. sapiens</i> females maintain the ancestral (plesiomorphic) configuration still present on the male Neandertal. The Neandertal male pelvis shares the female configuration, suggesting that anterior acetabular migration is a derived (autapomorphic) condition unique to modern human males. The anterior acetabular migration and associated ischiopubic modifications reflect a mechanical trade-off: adductor reorientation toward greater verticality increases sagittal-plane shock absorption at heel strike while reducing mediolateral stabilizing capacity. Regardless of whether this exchange confers a net advantage in long-distance walking, it requires empirical testing, like everything that we propose here.</p>