I've heard the opposite happened, namely that the reason why Africa is so Savanah is because of mastery of fire and a 'prisoners dilemma' of arson vs rival band

I've heard the opposite happened, namely that the reason why Africa is so Savanah is because of mastery of fire and a 'prisoners dilemma' of arson vs rival bands. Of course this is all second hand. I suppose weirdly both could be true at once if the mass killings came before fire did.