You are what you eat. And if you’re one of the apex predators that populated an unusual ecosystem 100 million years ago, researchers can determine both your meal plan and how your local food chain got so top heavy with giant carnivores, including dinosaurs and crocs.

Paleontologists have long puzzled over why the ancient river systems of North Africa were home to multiple apex predators. A new study provides a meaty answer, though there’s something fishy about its data on Spinosaurus, one