Dromaeosaurus albertensis, a two-metre-long carnivore and a fast runner, had a light skeleton with long legs. It lived in North America, 76 to74 million years ago. It was an agile pack hunter, enabling several individuals to attack large plant-eating dinosaurs. Powerful curved claws and rows of needle-sharp teeth helped get a grip on victims. D. albertensis was from the theropod group - dinosaurs that walked on two legs and usually ate meat. Studies have shown that modern-day birds evolved from small members of this group, and it is likely that Dromaeosaurus had feathers.