On the perilous Jurassic Period landscape of western North America, it was good to be big. Paleontologists have conducted a study scrutinizing bite marks left by meat-eating dinosaurs on the bones of sauropods - the familiar plant-eating dinosaurs with long necks, long tails and four pillar-like legs that were the largest land animals around - about 150 million years ago. Of about 600 bones checked, bite marks - often deep grooves left in stout bone - were detected on 68 of them, spanning 40 individual sauropods and representing at least nine species.