New research has revealed that baby and juvenile sauropods were a common food source for large theropod dinosaurs in a Jurassic ecosystem in what is now Colorado. The study, published in the New Mexico Museum of Natural History and Science Bulletin, reconstructs the food web of the Dry Mesa Dinosaur Quarry, a site teeming with fossils from around 150 million years ago.
Scientists analysed multiple lines of evidence, including chemical signatures in tooth enamel, scratch marks on teeth, biomechanical models, and fossilised stomach contents. They found that while adult sauropods like Brachiosaurus, weighing up to 60 tons, were too formidable to hunt, their young were vulnerable and easy prey for predators such as Torvosaurus and Allosaurus.
Lead author Cassius Morrison, a paleontologist at University College London, explained that juvenile sauropods were abundant, defenceless, and slow-moving, making them an ideal snack. Adult sauropods relied on their immense size and herd behaviour for protection, but their hatchlings emerged from eggs only a foot wide and were left to fend for themselves.
The ecosystem included at least six sauropod species—Brachiosaurus, Diplodocus, Supersaurus, Apatosaurus, Camarasaurus, and Haplocanthosaurus—alongside five theropod species. Co-author Steven Allain of Anglia Ruskin University noted that predators likely targeted juveniles, sick or injured adults, or carcasses, as hunting a healthy adult sauropod was extremely risky.
The Dry Mesa deposit, formed during a drought, preserved a wide range of organisms from small reptiles to the largest dinosaurs. The reconstructed food web contains over 12,000 unique food chains, highlighting a complex network with sauropods at its centre.
