The valley’s lagoons are all dry, the seasonal sand rivers stopped carrying water long ago, and the Luangwa’s huge hippo population has all taken up residence in the shallow trickle of the main river. It’s hot, there’s not a lot of space and disagreements between males are almost inevitable. When two males find themselves jammed together, one would normally defer to the other with a lowered head and by turning away. So long as only one male makes a claim for dominance, all is calm in the herd.

But when a new male moves in, and attempts to challenge the existing male for the breeding rights to his females, it’s clear that the resident won’t give up without a fight. I watched this happen today. It started with a series of exaggerated yawns, lasting 5 or 6 seconds that displays the male’s size and impressive canines.

Following this, the two males faced up to each other and alternately raised and lowered their heads out of the water. Just as one raises his head out of the water, and you think that the eye contact will bring on a proper fight, the other ducks under and avoids the confrontation. And so it goes on. Neither really wants to fight; it’s risky, costly in terms of energy and unpredictable. A protracted fight would leave both exhausted and unable to protect their herd. And at a time when there is little grass to replenish energy supplies, one or both my perish from the effort.

But it didn’t look like they were going to resolve it any other way, so the stand off continued. Eventually, the resident began a series of short charges, where he displayed his strength and sent a small spray of water towards his opponent. Not deterred, the intruder simply turned aside and waited.

These little encounters increased in intensity and frequency until the intruder was forced to meet the resident’s moves.

After a few rounds of this, the intruder began to go onto the offensive. Perhaps aware that the resident male had expended valuable energy during his previous displays, the intruding male began lunging towards the other with his mouth wide open, slamming it shut at the last moment and forcing huge amounts of water out to the side. For the resident, this constituted war.

But the resident was bigger and stronger than the intruder had anticipated, and it only took a few minutes before the larger male was pursuing the smaller newcomer through the herd and out of the water. He left with a large gash on his side from the male’s canine, and I left with a wet shirt from where the hippos had splashed me as they rushed past the hide.