The anatomy of the African lion heart is not well documented, and assumptions are made that the anatomy is comparable to that of the domestic cat. The increasing demand for veterinary intervention in the African lion warrants sound anatomical knowledge of the heart. The heart is situated caudal to the thoracic limbs between ribs 4 and 6. It is covered by the left cranial lung lobe, and cranial and middle lobe of the right lung, respectively, with a prominent cardiac incisure present on the right. Two pericardial ligaments are present, the A. coronaria dextra is dominant, and the Atrium dextrum and Auricula dextra possess a vast network of Mm. pectinati. The massive thoracic limbs, adapted to bring down prey, appear to restrict the cranial thoracic cavity, and as a trade-off, the thoracic viscera are situated more caudally. During intense activity, the heart and lungs compete against each other for space, thus limiting physical activity to short, intense periods. Capacity for sudden increase of cardiac output is facilitated by the extensive Mm. pectinati of the Atrium dextrum. Intracardiac injection is recommended on the right, ventrally in intercostal space 5. The two pericardial ligaments may help to stabilize the heart during intense activity.