Juvenile Sauropods Were Key Prey for Late Jurassic Predators

Recent research indicates that juvenile sauropods, the long-necked herbivorous dinosaurs, were a major food source for carnivorous dinosaurs during the Late Jurassic period, approximately 150 million years ago. The study, published in the New Mexico Museum of Natural History and Science Bulletin, utilized fossil evidence from the Morrison Formation in the United States to reconstruct a detailed food web of that era.

The findings suggest that young sauropods, lacking effective defenses and parental care, were particularly vulnerable to predation. Dr. Cassius Morrison of UCL Earth Sciences noted that adult sauropods like Diplodocus and Brachiosaurus were massive, but their offspring, hatching from eggs about a foot wide, took many years to grow. He explained that the sheer size of adult sauropods made it difficult for them to care for their eggs without causing damage, leading to a situation where, similar to modern baby turtles, young sauropods were left to survive independently. This lack of parental care made them easy targets for predators such as Allosaurus.

The research team analyzed fossils from the Dry Mesa Dinosaur Quarry in Colorado, a site known for its rich fossil record spanning up to 10,000 years. By examining factors like body size, tooth wear patterns, and chemical clues in fossil remains, they reconstructed the Jurassic food web in unprecedented detail. The analysis revealed that sauropods had more connections to plants and predators than other herbivorous dinosaurs, indicating their central role in the ecosystem.

The study also suggests that the abundance of juvenile sauropods as easy prey may have influenced the evolution of later dinosaur predators. Approximately 70 million years later, during the time of Tyrannosaurus rex, the scarcity of such prey may have driven the development of traits like stronger bite force, larger body size, and improved vision, enabling T. rex to hunt larger and more dangerous animals like Triceratops.