Deinonychus Antirrhopus Deinonychuses were vicious creatures that walked the earth about 100 million years ago during the Early Cretaceous period. Deinonychus is Greek for deinos, “terrible”; onychos, “claw”, and is genus of small, bipedal, flesh-eating dinosaurs of the suborder Theropoda, that lived during the Early Cretaceous period, which began about 136 million years ago. The scientist who discovered this dinosaur gave it this name because of the large upturned claw on each foot. Fully grown, this fierce theropod stood as high as 5 ft, measured 9 ft in length, and weighed up to 175 lb. Deinonychus was a strong run