The first carnivorous dinosaurs in the Triassic period were the Eoraptor and Herrerasaurus. Both dinosaurs were small and bipedal, with powerful hind limbs and long tails for balance. The later Coelophysis was also a meat-eater. Some of the first fossils of this dinosaur were found in the southwestern United States—and although it is debated, some scientists believe the creatures were the first to show evidence of a herding behavior.