According to some accounts, Hannibal took 37 war elephants across the Alps in 218 BC. The elephants traveled with his Carthaginian army during the opening phase of the Second Punic War against Rome.
Hannibal began the march from Carthaginian-controlled territory in Hispania, crossed the Rhône, and then led his forces over the Alps into northern Italy. The journey was extraordinarily difficult: the army faced steep mountain routes, cold weather, attacks from local tribes, and shortages of food. Many soldiers and pack animals were lost before the army reached Italy.
The number 37 should be treated as a historical estimate rather than an absolutely verified census. Ancient historians did not always agree on Hannibal's troop strengths, and later summaries sometimes give different figures. Even so, 37 is the conventional number associated with the elephants brought over the Alps. Most of the animals died during the subsequent campaign, while Surus is traditionally remembered as the last survivor in Italy.