Female often submerged during copulation. See above, under Submission. Self-defense against driving male. Mother and Offspring Nursery herds and calf creches. By both mother and calf.
Calf responds by lying prone.
Getting between calf and danger, mother confronting d or turning and slow tail paddling. Bulls often chase and sometimes kill small hippos, presumably males still in mother's care. Play Calves in catches engage in sparring matches and chasing. Response to Predators Diving and swimming away underwater. Reaction to people or vehicles by hippos exposed to shooting.