The eastern collared lizard (Crotaphytus collaris), also called common collared lizard, Oklahoma collared lizard or collared lizard, is a North American lizard that can reach 8–14 inches (20–36 cm) in length (including the tail), with a large head and powerful jaws. They are well known for the ability to run on their hind legs, looking like small theropod dinosaurs. Chiefly found in dry, open regions of Mexico and the south-central United States including Missouri, Texas, Arizona, and Kansas, the full extent of its habitat in the United States ranges from the Ozark Mountains to southern California. The collared lizard is the state reptile of Oklahoma, where it is known as the mountain boomer.