from the lower jaw have not yet been discovered, but they are expected to show opposing tooth-to-tooth wear. The ability to raise their heads well above the ground does not necessarily mean they browsed on items there, and the short neck of Nigersaurus would have restricted the browsing range compared to other diplodocoids. The adductor muscle of the jaw appears to have attached to the quadrate instead of the supratemporal fenestra. Both this and the other mastication muscles were likely weak, and Nigersaurus is estimated to have had one of the weakest bites of the sauropods. In addition, according to Whitlock and colleagues in 2011, the small, nearly parallel nature of the tooth scratches and pits (caused by grit, which would not be obtained as often by high-browsers) indicate that it ate relatively soft, herbaceous plants such as low-growing ferns. Because of the lateral orientation of the teeth, it probably would not have been able to chew. Nigersaurus wore its tooth crowns down faster than other dinosaurian herbivores, and its tooth replacement rate was the highest of any known dinosaur. Each tooth was replaced once every 14 days; the rate had previously been estimated lower. In contrast to Nigersaurus, sauropods with lower tooth replacement rates and broader tooth crowns are thought to have been canopy browsers. Grass did not evolve until the late Cretaceous, making ferns, horsetails, and angiosperms (which had evolved by the middle Cretaceous) potential food for Nigersaurus. Sereno and colleagues stated it was unlikely that Nigersaurus fed on conifers, cycads, or aquatic vegetation, due respectively to their height, hard and stiff structure, and lack of appropriate habitat. Wedel suggested that the evenly spaced teeth of Nigersaurus could have functioned like a comb, by straining water plants or invertebrates, similar to flamingos. He also suggested it could have low-browsed from short conifers and other low-growing plants. Head posture On the basis of microtomography scans of skull elements of the holotype specimen, Sereno and colleagues created a "prototype" Nigersaurus skull they could examine. They also made an endocast of the brain and scanned the semicircular canals of its inner ear, which they found to be oriented horizontally. In their 2007 study, they stated that the structure of the occiput and cervical vertebrae would have limited the upward and downward movement of the neck and the rotation of the skull. Based on this biomechanical analysis, the team concluded that the