Regarding the discovery of the dinosaur heart with the single aorta, your readers should note that this morphology is more likely to be related to high blood pressure than metabolic rate per se. The typical reptilian heart, with its incompletely divided ventricle and double aorta, is quite functional at separating oxygenated and deoxygenated blood. The reptilian heart also has the advantage of being able to shunt blood so that equal volumes needn’t be sent to the lungs and the body.