Theropods walked on two legs and were carnivorous. "Theropod" means "beast-footed" and they are some of the fearsome and most recognizable dinosaurs — including Allosaurus and T. rex.
Scientists have wondered whether large theropods — such as Giganotosaurus and Spinosaurus — actively hunted their prey, or simply scavenged carcasses. The evidence points to the animals working together as opportunistic hunters: they would bring down prey, but also eat animals that were lying around. When fossil-hunters found bones with bite marks on them, they wondered if theropods engaged in cannibalism. It appears now that the animals may have scavenged their own kind, but they didn’t hunt down their own.