As the dry season sets in, the small pools that are home to hippos begin to turn into death traps. The females that once shared this pool have all left, and this male can't stay around much longer. He needs water to keep cool and females to mate with. Almost all the hippos in the area have moved to the remaining deep water in the Luangwa river. In this stretch of the river one male rules, controling all the females. To have any chance of breeding, the incoming hippo must fight the dominant male. Ultra-slow motion shots show the clash of two mighty beasts. The outsider loses, but he lives. He has to retreat to shallower waters where no females will follow and his chance of fathering the next generation is over for now.