The effect of a panic among the war elephants was greatly dreaded by the generals who owned them; and Asdrubal provided his drivers with a knife and mallet, with instructions, if the elephant became unmanageable, to drive the knife between the junction of the head and spine. In the battle of Metaurus, this expedient was also employed. The Romans attacked them with such ferocity, that the elephants turned, and began trampling their own troops; and, in obedience to their instructions, the drivers slaughtered six while in their headlong flight, falling with them to the ground. This, however, did not prevent the utter rout of the forces; and, in a frenzy of rage, Asdrubal threw himself single-handed at a battalion of the enemy, and fell, opposed by thousands. It is evident that in these days the range of the African elephant extended farther to the north; and that they were much more abundant, is shown by some passages in the old works. Thus, when Scipio was about to invade Africa, the Carthaginians made great preparations to prevent his advance; and, according to Appian, a large number of elephants were taken in a short time, and trained for war. This could not have been done if they had to be sought at a great distance. They may have been found in Barbary, which would explain the ease with which re-enforcements were made in all these wars. When Scipio invaded Africa, Mago, the brother of Hannibal, proceeded against Italy with a new and magnificent army; and the vast array of elephants he drew up before the Roman cavalry on the field of Insubria, is said to have been almost unequalled in the annals of ancient warfare. Notwithstanding this, the Romans were successful. Scipio was followed into Africa by Hannibal; and the two warriors, both equally famous, met on the field of Zama. Hannibal had eighty elephants in line, a formidable array; but Scipio, aware that his horses were useless, sent them to the rear, and ordered his archers to direct their arrows at the trunks of the elephants of the enemy. So vigorous was the assault, that the elephants, panic-stricken, turned, and in a moment were rushing wildly to the rear; their trumpeting, and the cries of the dead and dying trampled under foot, producing an indescribable scene. The entire right wing of the Carthaginian general was broken, and, utterly routed, he retreated to Adrumetum; the action of his own elephants bringing to a close the second Punic war (201 B.C.). A treaty of peace was now arranged; and with due respect for the elephant, as an engine of war, the Romans bound the unfortunate Carthaginians to deliver up all their war elephants, and never tame others for military service. The elephants captured by Scipio were forwarded to Rome; and in his triumphal procession to the Capitol, they followed the sacrificial victims.