Something similar to this was on the National Geographic channel last week and the documentary said that the two bulls fought for hours, with one of the bulls splintering one tusk before he finally gave up the battle.
Notice in the first pic that the bull on the left has differing sized ivory and the shorter one seems to have differing curve that dosent apear to be a trick of perspective, nor dose it apear to be the result of a broken tip. This pic shows a broken tusk.
