In the wild western part of North America during the Jurassic Period, being big was like having a superpower for survival. Paleontologists recently studied bite marks left by meat-eating dinosaurs on the bones of sauropods, which were huge, plant-eating dinosaurs with long necks, tails, and strong legs. These paleontologists looked at around 600 bones from at least nine different kinds of sauropods, finding deep grooves on 68 bones from 40 individual sauropods. The researchers figured out that these marks weren’t from predators attacking live adult sauropods. Instead, they suggested that meat-eaters found the bodies of sauropods that had already died from things like old age or sickness. The study proposed that it was probably too dangerous for even large predators to take down adult sauropods, which were much bigger than them. The researchers didn’t find any evidence, like healed bite marks, showing that adult sauropods were usually hunted by predators. They thought that predators might have targeted the old, sick, or injured sauropods. Sauropods, the biggest land animals ever, appeared about 200 million years ago and stuck around until the dinosaur era ended 66 million years ago.

Smaller theropod dinosaurs like Allosaurus, Torvosaurus, Ceratosaurus, and Saurophaganax coexisted with sauropods during the Jurassic Period. Despite being smaller than adult sauropods, these theropods seemed to avoid hunting them. Instead, the study found wear on their teeth, indicating a regular consumption of young sauropods. The abundance of young sauropods may have provided a consistent prey source for theropods. Overall, the research suggests that large predators primarily encountered and preyed upon young and vulnerable sauropods in the Morrison Formation.