My money is on the one on the right.
Territorial disputes between Hippos can be settled quickly by the smaller bull showing signs of submission, or they can be settled by a full on fight if they are equal in size. In this incident which happened just in front of the lodge, the young bull who had taken a liking to the site was caught in a tight spot, behind him only rocks, so no escape possible. Forced to stand its ground, the fight continued for 20 minutes, the tusks can cause major wounds and even possibly death. At the end the larger bull gave the younger one a chance to escape, which he took, running on to the bank into the bushes.