Mago, thinking it a favourable occasion to attack the Romans as they were forming their camp, took most of his own cavalry and Massanissa with his Numidians and charged the camp, being convinced that he would find Scipio off his guard.
Scipio, however, had long foreseen what would happen, and had stationed his cavalry, who were equal in number to those of the Carthaginians, under a hill.
Surprised by this unexpected attack many of the Carthaginians as they wheeled sharply round at the unexpected sight, lost their seats, but the rest met the enemy and fought bravely.
Thrown, however, into difficulties by the dexterity with which the Roman horsemen dismounted, and losing many of their numbers, the Carthaginians gave way after a short resistance.
At first they retired in good order, but when the Romans pressed them hard, the squadrons broke up and they took refuge under their own camp.
After this the Romans displayed greater eagerness to engage and the Carthaginians less.
However, for several days following they drew up their forces on the level ground between them, and after trying their strength by skirmishing with their cavalry and left infantry, finally resolved on a decisive action.
Walbank Commentary