How did Hannibal get his elephants across the Alps?

Energy Expenditure as the Key to the Mystery

For decades, historians have debated which Alpine pass Hannibal actually led his army over. The research team’s calculations point to the Col de la Traversette Alpine pass. According to the model, it was both the shortest and the most energy-efficient route. The entire army would have needed 5.42 trillion joules of energy to complete it.

Other possible Alpine passes fared worse. For the route over the Col de Montgenèvre, the team calculated an energy requirement that was about 11 percent higher. The Col du Clapier, long considered the most likely route, would have required about 16 percent more energy. The route over the Col du Mont Cenis came in last, with about 19 percent higher energy consumption.

The model calculations also show just how much the march wore down the army. According to the calculations, soldiers on the Traversette route would have lost about 19 percent of their body fat reserves. This could explain the high death toll. According to the calculations, the elephants coped significantly better with the hardships. They lost only about four percent of their energy reserves. This could explain why many of them survived the crossing of the Alps.