The evidence for a four-chambered heart with a single aorta, Dr. Russell and his colleagues concluded, strongly suggested that this and perhaps many other dinosaurs had higher metabolisms than other reptiles. If this is true, they may have been warmblooded instead of coldblooded, like other reptiles, and thus could have engaged in more sustained activity in foraging and fighting, in chasing prey or escaping predators. Such advanced hearts are capable of distributing more completely oxygenated blood throughout the body.