Even Jurassic herbivores had to have a meat fix every now and then.

…scientists say they have evidence that the shell fragments were big enough to suggest that the hadrosaurs were intentionally chomping down on seafood, rather than accidentally eating some stray shell bits with their prehistoric salads.

The shell pieces also appeared in the majority of the poop samples over a span of 20 km (about 12.5 miles), which signaled to researchers that this was probably not just one herbivore gone rogue.

…The researchers believe the hadrosaurs only ate shellfish seasonally. It could have been that they switched over to shellfish when vegetation was scarce, or when they needed an extra calcium and protein boost, as they would during breeding and egg-laying season. For the most part, though, they probably stuck to their plant-based diets.

Herbivore dinosaurs may have cheated with shellfish — Quartz

hmmmm