Here's why:

* Teeth: Troodon fossils show they had sharp, serrated teeth, perfect for tearing flesh.

* Claws: They possessed large, curved claws on their hands and feet, ideal for grabbing and holding prey.

* Brain Size: Troodons had relatively large brains for their size, suggesting they were intelligent and adept at hunting.

* Fossil Evidence: Fossil remains of troodons have been found alongside the bones of other dinosaurs, indicating they likely preyed on them.

While there is some debate about the specific prey they hunted, the evidence overwhelmingly points to Troodons being carnivorous.