How do people know dinosaurs are carnivorous?

Carnivores have sharp teeth, which are used to rip apart meat. herbivores have flatter teeth which help them grind up plants.

Scientists also compare the physical attributes of living carnivores (sharp teeth, claws, etc.) with those of the dinosaurs to see if they are set up to be successful carnivores. There is also work done on the relative populations of the supposed carnivores to the data for supposed herbivores. Predators (carnivores) usually have a significantly lower population number than prey animals.

Additionally, some dinosaurs such as coelophysis and microraptor have been found with the bones of other animals in their stomachs.