This dinosaur didn’t have to worry about dentures. The Nigersaurus taqueti boasted 500 teeth, arranged in 50 rows across its jaw. When a tooth fell out, the teeth that had been lined up behind it would shift forward. Roaming modern-day Niger 80 million years ago, Nigersaurus didn’t use its long, snaky neck to munch on treetops, says Paul C. Sereno of the University of Chicago, a discoverer of the skeleton.
Instead, it grazed on ground vegetation. Sereno and his colleagues analyzed the dinosaur’s skull and found that Nigersaurus inner ears pointed down. The ears of tree-foraging creatures, such as giraffes, point up. The find is reported online in the November PLoS ONE. Sereno says paleontologists had never before considered that any long-necked herbivores, called sauropods, ate from the ground. “It took an extreme dinosaur to open our eyes to this cowlike behavior,” he says.