Dusk is a time of activity along the rivers of Africa. Life of the day and life of the night overlap. Also it is a time and place of great danger for those creatures whose lot it is to be captured and eaten by predators.
This mature lion is, however, not on the prowl. His wives do that. He is taking a stroll after his hot, daylong siesta. The river provides not only a place to drink, but the possibility of something interesting to observe and maybe even some easy prey.
I liked the positive and negative shapes of the rocks and water and reflections. African rivers are subject to sudden floods. The ancient rocks are sculptured by the river. In the mud deposits are the textures of the hoof prints of the grassland game. Perhaps they had just been drinking and have moved out of the lion's casual approach.