In 218 BC, the Carthaginian general Hannibal undertook a daring action to surprise his bitter enemy, Rome: he crossed the Alps with 40,000 soldiers, 7,000 horses, and 37 war elephants with the intention of invading Italy. For centuries, historians and archaeologists have debated which mountain pass the Carthaginian army used. An interdisciplinary study published in the journal Proceedings of the National Academy of Sciences (PNAS) has launched a new theory with a highly innovative approach: bioenergetics. The research, led by the University of Oxford and Friedrich Schiller University Jena, indicates that the Col de la Traversette, located at an altitude of 2,914 meters on the current border between France and Italy, was the chosen route because it required less energy consumption, especially for the elephants.