I read several articles on the web describing what happen during the battle of Zama. I still can't understand how did the Great Hannibal lost the battle so badly to the Romans despite he won so many great battles against his enemies before.

The advantages I can see for the Romans are they found a way to defeat the elephants, discipline legionaries, and led by a great general too.

The advantages of Hannibals are 80 elephants, season veterans who defeated the Romans so many times, brave mercenaries, uneven matched cavalries favor to Hannibal side.

Both sides numbers are almost equal.

What happen to Hannibal himself? Why did he chose to deploy his army in the manner where it leads to chaos? Or did he not had anticipated it?

Can someone enlighten me with more details on this? Own opinions are welcome too.