AI opponent earned 2.5 million XP in one game. How?

My brother and I and his 2 daughters played against 5 AI (his daughters were on 1 PC, so 3v5). We enabled the “speed always wins” cheat to let everyone (including the AI) gather and build pretty much instantly. At the end of the game (we won, but it took nearly 2 hours!), one of the AI players, Akbar, had gained nearly 2.5 million experience. The rest of us (including the other AI) each had around 50-100 thousand. How can this be??

Probably cows, cows generate XP for India